# Long cranking after sitting 1 week cure?



## 11th Indian (Feb 15, 2018)

My 72 cranks for a long time to start after sitting for a week,. I know this is a common issue with the fuel evaporating and the bowls are dry. 
Once the car is started - it will re-start hot of cold immediately.... for a few days.... I just dont drive it daily.

I was wondering how does anyone else with this issue deal with it? Do you just crank it a few times for a few seconds?
Small squirt bottle with gas, fill up the bowl first ?
Electric fuel pump?

Thanks!


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## ajluzi1957 (Mar 22, 2017)

Same issue with me, though generally longer than a week. I just crank it for 4-5 seconds, then pump the pedal twice and it fires right up


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## PontiacJim (Dec 29, 2012)

11th Indian said:


> My 72 cranks for a long time to start after sitting for a week,. I know this is a common issue with the fuel evaporating and the bowls are dry.
> Once the car is started - it will re-start hot of cold immediately.... for a few days.... I just dont drive it daily.
> 
> I was wondering how does anyone else with this issue deal with it? Do you just crank it a few times for a few seconds?
> ...


Electic fuel pump back at the tank seems to be the best solution assuming no cracked rubber lines sucking air, dirty fuel filter, problem with a fuel line, etc..

Ethanol in the gas is the problem. The gas will evaporate when sitting long periods. Common problem. My brother added the electric fuel pump to 2 of his older cars and it solved the issue as well as hot start issues. You don't need a huge killer pump and you want to keep your factory fuel pump to act as a regulator.

If you do a search of th forums you will find other answers/ideas as this has been covered several times.


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## bigD (Jul 21, 2016)

X2 on the part time electric pusher pump. This works if your accelerator pump will squirt gas. If not, you'll need to pour or squirt a little gas into the primaries, by hand. My last bracket car had a RobbMc mechanical pump, only. So, when cold, I poured in a little gas from a small plastic bottle.


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## 11th Indian (Feb 15, 2018)

Thanks guys...
Going to try the squirt bottle with gas first, ifs thats a PIA, then the electric pump near the tank.

On a previous car I had an electric pump and a pre -oiler. Was like having a preflight check list.


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## 1966tempest (Jul 14, 2015)

11th Indian said:


> My 72 cranks for a long time to start after sitting for a week,. I know this is a common issue with the fuel evaporating and the bowls are dry.
> Once the car is started - it will re-start hot of cold immediately.... for a few days.... I just dont drive it daily.
> 
> I was wondering how does anyone else with this issue deal with it? Do you just crank it a few times for a few seconds?
> ...


Install An electric pump, hook it up to your key, if it's sits a while Turin the key on for a few second then crank her up.. ofcourse, you will want a filter before the pump, and use a relay, and perhaps a return line and a regulator.. it don't sound to simple now..
There are pumps that don't require a return line..or regulator but I would use a relay....


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## BLK69JUDGE (Jun 10, 2010)

I dont know about an electric pump and the mechanical pump hooked up in tandem...

here is my experience ....

1988-89 ..... early summer.... girlfriend has 81 Z-28 with a warmed up 350 th350 t top last of the cool body style...

615 am ,,, her car is under the carport in front of the house and time to go to work.... I am lockin up the house

to leave also ...

I hear her crank it over and BOOOOOOOM !!!!!!! house windows shook ...my horns honkin on my 68 gto alarm is goin off..

sounded like a quarter stick of dyno just went off !!

I whip the front door open and look towards the carport.... I see the neighbor stoner kid flyin out his open bedroom window and rollin into the front yard in his undies .... yellin WTF !!!

my girlfriends sittin in the car with smoke rollin out from under the hood ... by the windshield and fender gaps and under the car
I have to peel her hands off the wheel ....

ran to the kitchen for a fire extinguisher .... as shes just screaming in the front yard with the neighbor

by now his parents are outside as we all left for work around the same time..

I pop the hood ... NO FIRE .. but 1 morroso valve cover is layin on the inner fender totally ripped off the engine 
and the other has 2 T bolts
bearly holdin it on .... WTF ???


well the electric pump blew a hole in the diafram in the mechanical pump and pumped fuel into the crank case

with the mallory ignition and sittin overnite and the fumes building up .... it blew the valve covers off when she tried 

starting it

timing cover was all swollen and the oil pan too .... had to pull the motor .... swap the m out too

I still have one of the heavy steel wide valve cover bolt spreader bars ,,, on a key chain bent up at a mild V shape

so .............

I dont think I will ever do it ... have both electric and manual together.... 

but ..............

Scott

just my .02 sense worth


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## john23 (Mar 6, 2016)

BLK69JUDGE fun story, thanks


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## Onebrokegoat (Sep 27, 2018)

Holley Sniper EFI. You’ll never have starting problems again. This also includes an electric pump btw.


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## Nicholas (Jan 16, 2017)

Electric fuel pumps are also noisy. I have one on a non Pontiac vehicle. How is your choke working?? On my '71 GTO, I converted the choke to electrical and the motor does start better after sitting a while. I was experiencing some problems similar to yours. If you do install an electric pump, do you plan on keeping it on continuously or just when you want to start the car after sitting a while?? If you do use it just for starting, in addition to possibly putting it on a relay, wouldn't you also have to install a toggle switch to control on and off??


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## PontiacJim (Dec 29, 2012)

BLK69JUDGE said:


> I dont know about an electric pump and the mechanical pump hooked up in tandem...
> 
> here is my experience ....
> 
> ...


Interesting story and gave me a few things to think about. I did a little web researching and put this together: https://www.gtoforum.com/f178/electric-fuel-pump-133157/


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## 1966tempest (Jul 14, 2015)

Nicholas said:


> Electric fuel pumps are also noisy. I have one on a non Pontiac vehicle. How is your choke working?? On my '71 GTO, I converted the choke to electrical and the motor does start better after sitting a while. I was experiencing some problems similar to yours. If you do install an electric pump, do you plan on keeping it on continuously or just when you want to start the car after sitting a while?? If you do use it just for starting, in addition to possibly putting it on a relay, wouldn't you also have to install a toggle switch to control on and off??


I run a Hollley blue pump on my vette and a red pump on my tempest.. they are not silent but quiet, if you think its noisy, chances are it needs servicing.. I am sure other brands may be louder than others.. but overall if you can hear the pump when your car is at idle, rebuild or replace..


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## vvalkid (Oct 7, 2015)

I have had the same issue with my 67. Original intake manifold, Edelbrock carb. If it sits more than a couple days I have to pump the snot out of it to get er started. Then it starts right up hot or cold no problem. Took 11th Indian advise and just crank it 3-4 seconds, pump it 2 times and it fires right up.
What I don't get is that I am working on a 67 Firebird that has a 350 motor Edelbrock intake, Edelbrock carb and it can sit for 2 weeks, I pump it 2 times and it starts right up.

So on the GTO I clamped off the fuel line right b4 the carb, let it sit for a few days, and it still had the same starting issue. I wanted to rule out fuel leaving the bowls via fuel line. Hmmmmm. I don't get it. Why one car performs so differently than the other


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## PontiacJim (Dec 29, 2012)

vvalkid said:


> I have had the same issue with my 67. Original intake manifold, Edelbrock carb. If it sits more than a couple days I have to pump the snot out of it to get er started. Then it starts right up hot or cold no problem. Took 11th Indian advise and just crank it 3-4 seconds, pump it 2 times and it fires right up.
> What I don't get is that I am working on a 67 Firebird that has a 350 motor Edelbrock intake, Edelbrock carb and it can sit for 2 weeks, I pump it 2 times and it starts right up.
> 
> So on the GTO I clamped off the fuel line right b4 the carb, let it sit for a few days, and it still had the same starting issue. I wanted to rule out fuel leaving the bowls via fuel line. Hmmmmm. I don't get it. Why one car performs so differently than the other


Could be the original cast iron intake and exhaust crossover under the carb versus the aluminum intake which dissipates heat much better. You know that the '67 intake was unique to that year and has a heat channel that goes directly under the carb? You have to make sure you use the correct gaskets - or you will have problem. 

I included a picture of the '67 intake with the heat channel that goes directly under the carb versus the '68 and up intake which eliminated this.


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## 11th Indian (Feb 15, 2018)

Confirmed the carb seems dry. Let the car sit 7 days. Used a small squeeze bottle and poured about an once of gas in the float bowl. Started immediately. Sat over night and started right away for the last few days. Simple process, but it will get old fast.


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## PontiacJim (Dec 29, 2012)

11th Indian said:


> Confirmed the carb seems dry. Let the car sit 7 days. Used a small squeeze bottle and poured about an once of gas in the float bowl. Started immediately. Sat over night and started right away for the last few days. Simple process, but it will get old fast.


Simple solution. Use your windshield washer fluid tank/pump. Fill the tank with gas and run a small diameter gas line from a weed whacker from the electric pump outlet to the top edge of the carb and clip it on with a clothes pin so as not to crush the line. Then when you are ready to fire up, hit the control button for the wiper washers to prime the carb and you are good to go.

Remember, there are no problems, _only solutions_ - and all 'ya gotta do is ask. :lol:


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## 11th Indian (Feb 15, 2018)

Maybe a gas and meth mix, I can hit the switch at WOT too.....


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## vvalkid (Oct 7, 2015)

Jim, I could also use that same set up and run the tube to the my console next to the driver seat, and fill the reservoir with my favorite adult beverage. Your a genius!!!


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## PontiacJim (Dec 29, 2012)

vvalkid said:


> Jim, I could also use that same set up and run the tube to the my console next to the driver seat, and fill the reservoir with my favorite adult beverage. Your a genius!!!


Well, if we are going for adult beverages, I'd install a large AC condensor, you know, they look like a radiator. Set it out in front of the radiator so it gets a lot of cool air flow, and use it as the holding tank for my libations. On the inbound line to the condensor I would plumb a small O2 tank to pressurize the condensor with a few pounds of pressure. Then plumb another line out the outlet side to a drag race style cool can loaded with dry ice, then bring the line into my car under the console connected to a Seltzer water nozzle head connected atop the console with a cup holder and cup below. When you felt the desire for that adult beverage of choice, just press down on the Seltzer nozzle and let the pressurized, and cold, libations flow into your cup 'til it runneth over. Just expanding the idea 'cause your idea was OK, but who wants a warm adult beverage that chances on the 12-volt windshield washer motor made in China quitting on you just at the time of need? :yesnod:


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## cij911 (Oct 25, 2017)

I am glad you figured out the problem, but I am at a loss as to why your gas is evaporating after sitting for a week. As I mentioned previously, my tri power bowls still had fuel in them after sitting for quite a while.


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## 11th Indian (Feb 15, 2018)

cij911 said:


> I am glad you figured out the problem, but I am at a loss as to why your gas is evaporating after sitting for a week. As I mentioned previously, my tri power bowls still had fuel in them after sitting for quite a while.


Could be a combination of the type of Q-Jet I am running, content of the gas and under hood temps....


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## Ricker (Sep 5, 2018)

I live in the high, dry Nevada desert, where EVERYTHING evaporates rapidly. My bowls dry out within a couple weeks and I make sure my automatic choke is fully functional, the battery is at full charge and I crank. Putting the pedal to the floor one time sets that choke. It does not take but a few moments to draw the fuel up from the tank, refill the bowl and light 'er up. Always.


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## vvalkid (Oct 7, 2015)

I agree with cij911. I am at a loss too with why the fuel in one of my cars goes dry after a few days, and the other car doesn't go dry even after a couple weeks. Maybe someday we will have an answer.


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## PontiacJim (Dec 29, 2012)

vvalkid said:


> I agree with cij911. I am at a loss too with why the fuel in one of my cars goes dry after a few days, and the other car doesn't go dry even after a couple weeks. Maybe someday we will have an answer.


I believe I already suggested why. Do you have an original 1967 cast iron intake or do you have a later cast iron intake?

Have you ever tried non-ethanol gas or an additive like Stabil 360?


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## vvalkid (Oct 7, 2015)

Yep you did Jim. I do have the original intake with that heat channel. I do have what looks like a 3/8 in. aluminum riser under the carb. I have replaced that intake to riser gasket with one from NAPA a while back. I checked a couple catalogs for a different gasket but haven't found one. Do you know where I can get the one you are talking about or have a part #?


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## PontiacJim (Dec 29, 2012)

vvalkid said:


> Yep you did Jim. I do have the original intake with that heat channel. I do have what looks like a 3/8 in. aluminum riser under the carb. I have replaced that intake to riser gasket with one from NAPA a while back. I checked a couple catalogs for a different gasket but haven't found one. Do you know where I can get the one you are talking about or have a part #?


OK, this is assuming the problem is a heat soak or gas evaporating problem. It could be other things, but this is typically the issue - ethanol gas.

Here is an example,which is the correct gasket along with a stainless steel heat shield gasket/shim. https://quadrajetparts.com/quadrajet-base-gasket-thick-pontiac-1967-p-110.html Personally, the instructions say the heat shield goes under the gasket, but stainless steel is pretty rigid material and I can/t see it sealing well directly under the carb base without a gasket - and you could wind up with a vacuum leak. I have seen similar and a thinner paper-like gasket was used between the carb base and the heat shield.

You can also buy the parts separately. Summit has them and most autoparts stores can order them as well.

Bottom gasket for the intake is Felpro 60043 - https://www.summitracing.com/parts/fel-60043/recommendedparts

The stainless steel heat shield is Felpro 60731 - https://www.summitracing.com/parts/fel-60731/recommendedparts

Top gasket under the carb without the open front groove is Mr. Gasket 56C - https://www.summitracing.com/parts/mrg-56c

You could also fill in the heat passage under the carb with furnace cement. This would block off the under carb heat if you wanted to go that route Rutland brand Chimney Sweep Furnace Cement.

By "3/8" riser" I assume a solid aluminum spacer plate? Aluminum will still transfer heat if it is a solid spacer keeping in mind that the engine/exhaust is still dumping heat into the open manifold slot under the spacer when you shut down the engine, and perhaps more so as engine temps generally increase because coolant flow has stopped. I might still try the block-off plate under the solid spacer to further keep heat off the spacer - or remove the aluminum spacer and go with a phenolic spacer which would be better than the aluminum.


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## Stereolab42 (Apr 6, 2018)

Interesting thread. On my '68, with the original Quadrajet (and presumably a repro OEM-style fuel pump), on a bone-cold start it will always fire up with two pedal pumps and five seconds of cranking. Warm starts throughout the day are instant. Gas is 91 octane California.


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## vvalkid (Oct 7, 2015)

So what I ended up doing is taking the ol Goat out for a drive, parked it for 3 days and yep, had to crank it for a while then she fired up. So after she started, I let er idle for about a minute so as to not let the engine warm up and shut er down. Waited for 3 days, went to start it and she fired right up. 
Conclusion,,,, definitely fuel in the carb bowl is evaporating after the engine is good and hot. Probably from the reasons stated previously.
The Fix,,,,,, After a drive and the engine cools down, in the evening, b4 calling it a night, I just go out to the garage and start the engine, let it run for about 15 seconds and shut her down. I have found that even if its been a week, when I go and start it she fires right up. NO parts needed, I just have to remember to fill the carb bowl after the engine cools. Not so bad, and its nice to hear the motor just before nighty night


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## PontiacJim (Dec 29, 2012)

vvalkid said:


> So what I ended up doing is taking the ol Goat out for a drive, parked it for 3 days and yep, had to crank it for a while then she fired up. So after she started, I let er idle for about a minute so as to not let the engine warm up and shut er down. Waited for 3 days, went to start it and she fired right up.
> Conclusion,,,, definitely fuel in the carb bowl is evaporating after the engine is good and hot. Probably from the reasons stated previously.
> The Fix,,,,,, After a drive and the engine cools down, in the evening, b4 calling it a night, I just go out to the garage and start the engine, let it run for about 15 seconds and shut her down. I have found that even if its been a week, when I go and start it she fires right up. NO parts needed, I just have to remember to fill the carb bowl after the engine cools. Not so bad, and its nice to hear the motor just before nighty night


Really not a "fix." We call that a "patch." Just thinking out loud - Firing it up and shutting it down puts more where and tear on the starter and may be washing the cylinder walls down with gas and accelerating ring wear when you fire it back up. :thumbsup:


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## Praxis (Feb 23, 2014)

I have a small electric pusher at the tank, switched separately so I have to turn it on and off, but power from ignition key. Pump only has a max pressure that is low enough it doesn’t need a regulator. After sitting, ignition on, pump on, when pump has filled the lines and bowls (pump slows and tone changes) I shut the pump off, give the accelerator a stab and turn the key to start, fires right up. Added advantage of this: if my mechanical pump fails I can use the electric to get home.


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## cij911 (Oct 25, 2017)

Praxis said:


> I have a small electric pusher at the tank, switched separately so I have to turn it on and off, but power from ignition key. Pump only has a max pressure that is low enough it doesn’t need a regulator. After sitting, ignition on, pump on, when pump has filled the lines and bowls (pump slows and tone changes) I shut the pump off, give the accelerator a stab and turn the key to start, fires right up. Added advantage of this: if my mechanical pump fails I can use the electric to get home.


Can you provide more information on your setup? Pump manufacturer and model #, wiring, etc? Do you have a return line as well ?

Thanks


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## Praxis (Feb 23, 2014)

I am looking for the details of the pump, should have them later today. You can wire it to any switched power source you want, preferably one not commonly in use, or run hot direct from fuse panel to switch, then to pump. My 1967 originally had a return line from the factory. That line is no longer in use, when I installed a new stainless steel tank and lines the new sending unit I got had no provision for return, and when I had the motor built by a guy who builds motors for a pretty famous NASCAR driver (466 ci, >500 hp, >600 ft lbs) he used a mechanical pump that did not have return, so the new stainless line is there but capped off. The pump I use has a max pressure of 4 psi so won’t overcome the needle and seat, plus I only use it to prime anyway. 
I hope to add the manufacturer and part number by later today. Pump is about 2” x 3”, makes a only slightly audible ticking sound when on, cannot be heard when engine running, and is very lightweight.


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## Praxis (Feb 23, 2014)

The pump is a low pressure flow through design, 1 1/2-4 psi, Facet FEP42SV, by Purolator.


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## Lemans guy (Oct 14, 2014)

The distillation curves for modern gas are low compared to the 1960's....E-10 summer blend is about 140 degrees where you really notice the evap change....pure gas more like 170 degrees. So you get a benefit from pure gas in preventing the evaporation.

we all are dealing with 3 kinds of heat and 2 related problems that overlap. the heat is conductive, radiant and convective. and they all matter. the problems are heat soak after shutdown and vapor lock during operation. you may get none, one or the other or both. all are heat related.

so to start first beat the conductive heat, metal to metal transfer with a phenolic spacer that reduces heat transfer to carb. For many this alone fixes their heat soak. also check fuel lines for touching metal parts of intake or engine where conductive heat can be transferred.

next Radiant heat, this effects us all but in particular guys like me who run a Quick Fuel carb or a Holley where the float bowls hang out over the intake manifold. Radiant heat from the manifold usually 200+ degrees rises up thru the air and heats the gas, especially after shutdown when no air from driving or fan is being pushed back over engine and reducing this effect. The fix for this is radiant heat shieds, Holley, Mr Gasket both sell them. I go the extra mile and put DEI radiant heat tape under my 2 shields and sandwich in a phenolic spacer. Quick Fuel also sells a "cool carb" plate which is a similar one piece set up but you cannot use with an open crossover. which I run, because I like the way it instantly vaporizes the fuel.

Next is Convective heat. when you shut the car off it becomes an oven under there and the air is heated by the hot engine and exhaust manifold. that heat surrounds everything and heats it up. Easyist thing open the hood like at the car show this will greatly reduce temps. when you come home from a drive at shutdown open the hood in the garage and leave it open. You can retest if your gas is evaporating at the same rate. or install fans to blow after shutdown. or both.

Now the problems encountered "Vapor lock" occurs on the suction side of the pump, the suction creates a vacumn and that reduces the atmospheric pressure so gas will vaporize at an even lower pressure. This causes vapor on the suction side of the pump and the car will stall when driving. The factory cure was a return fuel line to the tank. First from a fuel filter that had a return and later direct from the fuel pump to the tank. this keeps the gas always moving, keeps it cooler and also does not allow a vapor to form as it. that is why fuel injection does not have these issues, it is under pressure and raises the temp of the evaporation. Just like your radiator cap does it adds pressure to increase boiling temp.

So the best beat for vapor lock is a return line to the tank. Best way is off the fuel log right at carb and that keeps the fuel cool up to the carb because it is not sitting still and heating up in the lines like it does with a dead head pump. but a return line from carb, filter or at the pump is the answer for vapor lock.

back to heat soak. Keeping the fuel lines cool is often overlooked DEI sells fire wrap and heat insulating wraps for fuel lines. With velcro so you don't even have to remove the line, or solid so you can slip over. Summit jegs all sell it, keep the lines cool so after shutdown they don't heat up and boil over into the float bowls and heat the bowls up more.

I think Sta-bil Marine 360 gas additive helps a bit, not a substiute for the above but it is designed to prevent vapor loss when gas is sitting and has strong vapor presence. A bit of that helps a tad.

I run an open crossover and E-10, but do the above to keep fuel cool in carb lines and above throttle plate.............I like it real hot under throttle plate!

I have taken temps extensively under hood and have a see thru sight glass on the Quick Fuel. I can see if heat soak is evaporating gas after shutdown, and these things reduce it.


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## Lemans guy (Oct 14, 2014)

Also remember that gasoline is heavier than air, and so are gasoline vapors. That is why your Gas hot water heater sits on 2 cinder blocks in the garage. It is a safety measure for spilled gasoline.If you spill gasoline in a room, garage the gasoline vapors will fill the garage floor first about a foot high then they will start to rise. Your Hot water pilot light will still cause the vapors to explode and ignite once they get to that height. The rise is a small safety measure.

I always turn off the gas to my water heater when working on fuel lines. Turn it back on when done. so the pilot light is off.

Remmember the proper method to start a cold carbuerted car is 2 to 5 prime shots from the gas pedal (each engine a tad different) with the last one being all the way to the floor to set the choke.

Try this. Get in the car on a cold start and the very first thing you do is 3 prime shots the last one all the way down and hold it for 10 seconds. then let up. Now get your sunglassess put your jacket in the back, st your music right, put on your seat belt, roll down your window etc. If you are good you can waste 30 seconds on this, if you are the Man a whole minute.

Now turn the key to crank and see if she fires. This will often get you a nice clean cold start because you leveraged physics. The cold gas does not vaporize as well as the hot. The gas moves slow, but it is heavier than air, so while you are fiddiling around is is dropping down through the intake runners and settling over the valves, when you crank a vaporized mixture is immediately sucked in.

Now when you rush, you pump the pedal 3 times and crank you often are sucking in air as the gas vapors have not yet settled over and reached the valves. That is why we get it to fire a few seconds later, the vacumn sucks the vapors down when you try it a second time. So if you are not in a hurry, try this patient method. You find nothing is wrong with the car, you are just used to fuel injected cold starts. 

The reason I like to hold the last pump to the floor 10 seconds is all that gas you just shot in from the squirter is on top of the throttle plate, by holding it open you ensure a good dump into the intake instead of making the gas have to thread thru that .020 gap between the throttle plate and the carb wall. Now the intake will slowly fill with vaporized gas. Sometimes it will fire instantly, sometimes a few seconds, but waiting a bit puts physics on your side, and it is sometimes hard to fight the laws of nature.


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## 11th Indian (Feb 15, 2018)

https://www.knfilters.com/eci?gclid=EAIaIQobChMIsoG0jLmY4AIVw4KzCh3lSQ8nEAAYASAAEgJehPD_BwE

Interesting product, ..... A bit pricey though. 

I wonder if a spacer with a fuel injector and a power circuit, spring loaded toggle switch....


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## PontiacJim (Dec 29, 2012)

11th Indian said:


> https://www.knfilters.com/eci?gclid=EAIaIQobChMIsoG0jLmY4AIVw4KzCh3lSQ8nEAAYASAAEgJehPD_BwE
> 
> Interesting product, ..... A bit pricey though.
> 
> I wonder if a spacer with a fuel injector and a power circuit, spring loaded toggle switch....


Very interesting. I can see an application for this. But, I see your question is built off this item. So here goes:

You would need an electric fuel pump to provide enough pressure to spray through the injector. 

You might use a spacer plate drilled for a brake line adapter like this - https://www.amazon.com/Brake-Adapter-Female-Inverted-Flare/dp/B01KNGVH8E I would braze up the end of the adapter where it will go into the plate and then drill a 1/16" hole in it so as to regulate the gas flow like a carb jet would do.

Then attach a 5/16" brake line to the adapter fitting and connect it to a "T" running off the steel line going into your carb - let's call this a "jumper" line. BUT, you will need an on/off valve to control the fuel flow. Plumb/ wire in a nitrous fuel shut-off solenoid somewhere in the 5/16" "jumper" line.

When you are ready to fire up the engine, you energize the nitrous solenoid to its "open" flow position. When you crank the engine over, you will be using the factory fuel pump to pass fuel through your "jumper" line that will dump gas directly into the intake plenum below the carb throttle plates. Engine should fire right off, then flip the switch to shut off the nitrous solenoid and "Jumper" line by which time the carb bowl had filled up and you are now running off the carb.

If the heat soak is still affecting the start, then you would need to run a separate line off an electric fuel pump at the tank ("T" off the existing gas line at the tank) to the nitrous solenoid, bypassing the factory fuel pump altogether.


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## 11th Indian (Feb 15, 2018)

That system is rated for 6 to 25 psi. As its only needed for a cold start assist I wonder if residual fuel line pressure from the mechanical pump would work. Its designed to work with a low pressure mechanical system.


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## Lemans guy (Oct 14, 2014)

Basically you already have a fuel injector.....it is called an accelerator pump...and it does not need a computer or all that stuff...just your foot

A 30cc acc pump pumps 3cc of fuel with each compression.......10 compressions = 30cc.....

A 50cc acc pump pumps 5cc of fuel with each compression........10 compressions = 50cc...

When you press the pedal before a cold start the pump squirts most of the fuel goes into the intake, 3 pumps say 9cc....if you tip the wet throttle plate for a few seconds before starting you make sure it is all in...

This contraption will do the same thing, with a better job of aerating the fuel a tad faster. But not much of a difference, and just waiting a few seconds will even that up. Remember it is not vaporized really, it needs heat for that, ......but aerated with the injector.

Now like PJ said, is heat soak totally boiling your bowl dry after driving or in a week. If before a cold start you take off the air cleaner and look down the carb and see if you get 3 strokes of gas from the acc pump.......if so you may have some heat soak but that is enough gas to start and the mechanical pump will quickly fill the bowl.

Some guys like EFI, and some may prefer this system. But you can already squirt gas into the intake before starting.....as far as it helps all through the band to richen the mixture......

Most guys I see are already running rich, lots of carbs do, it starts and runs ez when on the rich side. So they leave it there. You can curve a carb in to run real great, but if you ddon’t Want to this I suppose can make up for it....

Novel idea, but remember,....it can only make the carb richer, not leaner.......since unlike EFI it does not control the total fuel deliver...

A carb is basically an “organized leak” I suppose.....but still can be efficient.....:nerd::nerd::nerd:


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## 11th Indian (Feb 15, 2018)

Its my understanding that for the accelerator pump to work, it must have something to ………… pump. 

After a few days, my car has fuel in the fuel line, but nothing in the bowl. Doesn’t matter if its 20 or 90 degrees. If I fill up the fuel bowl with gas from a small squeeze bottle and don’t even drive the car, its dry in 3 to 4 days. 

I temporarily switched out the stock fuel line for one with a glass filter, to see if its filled -and it also goes dry in about 1 week,. So…I need about 3 , four to five second cranks to start the car. Versus s squirt from a squeeze bottle of gas and the car starts just after the starter engages the flywheel.

My previous experience with LS engines and fuel injection had me wondering about that product. Engines starting and running for few seconds with the fuel pump unplugged - just on residual line pressure.


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## Lemans guy (Oct 14, 2014)

Have you considered that gas may be leaking from the bowl?......I have sight glasses in my fuel bowls and can see the levels, a vert small amount will evaporate as long as it is not too hot. At 20 or thirty degrees if the whole bowl evaporates in 3 days,...with not even enough for an accelerator pump squirt,...that may be more than evaporation.

Power valves can stick open and some Q-jet bowls are notorious for bottom leaks. I am sure you already know this, just thinking out loud here.

You can put the carb on a bench fill the bowls and watch the bottom.....is there a slow leak? From bottom, a gasket etc. even winter blend gas does not evaporate that fast in a sealed bowl when that cold.

Low pressure electric pumps seem to work for some,...but note that explosion on th 68 and be careful. And don’t use screw on hose clamps on fuel lines.....if you use rubber lines use good ones like Oiteker clamps...or Use AN fittings.

If you have a carb on the bench with gas, make sure you turn off any gas pilot lights etc...

One last note if you have a return line to the tank that is plugged use it. That is really the hardest thing to put in in a return system. Just put in a sender with a return,.....and use a mechanical pump with a return or run a return from up near carb.....keep the fuel cool and no vapor lock from a dead head system...

:nerd::nerd::nerd::nerd:


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## 11th Indian (Feb 15, 2018)

I don’t see any residue or leak, or ever smell gas in the garage. The carb and manifold seem dry all the time. I also thought my fuel pump may have a weak diaphragm, and maybe the fuel is draining back, I do have a return line. This is a stock QJet on a low compression 400 dog motor.

It seems the gas is evaporating pretty quickly. I don’t know if it’s a regional issue. I have small bottle of fuel and unless its very securely closed as it should be, it will evaporate in hours. I can see the level going down by the next day. Don’t remember that happening before….

If I still have this issue with the next engine / build I would consider the use of an electric pump just used to prime the system.


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## Lemans guy (Oct 14, 2014)

Yes, modern gas especially winter blend is very volatile. It has a low Distillation curve. An electric pump would solve that evap.

Also I use Stabil Marine 360 stabilizer,....you might try all the auto parts have it. It prevents a little bit of that evaporation though not all and not a cure all. sometimes I have found that different gas stations have a little differrent blend and E-10 s more volatile thanpure gasoline, so you might have better luck with that.

Heat of course leads to better vaporization that is why a hot start is so ez and also so many gas fumes still in the intake.

A leak can be running down inside your intake, you won"t see it outside and once the gas spreads out on the intake floor it will evaporate in a few days.

Keep stuff as cool as you can and maybe try to put different blends in a coffee can with lid and a straw to simulate a carb vent. If you could get the same cc that the float bowl holds you might be able to get an accurate measure of the evap. you could try it with a little stabil 360 as well.

some bleed off will happen but if you can get just enough for a few good squirts from the acc pump it will still start......anyway you are on it and I am sure you can improve it a bit!!

and do you run a hood blanket, those things really make it hot under there

good luck:nerd::nerd::nerd:


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