# Hard starting when hot(ish)



## gjones (Oct 8, 2012)

Just ran 'er up the road then let it idle in the driveway for a spell. She run around 195-200 degrees on the road, a solid 205 in the drive. (87 degrees outside in the shade, 99+ in the sun). Shut off and let it heat soak to 220 degrees (doesn't ever get above 220). Starts hard. Cranks fine, but you have to put your foot 3/4 or all the way to the floor and crank it from anywhere between 4-6 seconds, then it starts. Annoying. Backed it into the garage (90 degrees in there) shut it off. Let her sit about 10 minutes at 210-220, then cranked it up, temp went to 190. Shut off and let sit 10 minutes at 205. Started easier with the foot at half way, 2-3 seconds. Let sit at 195 for 5 minutes. Cranked right up with the foot just past idle, sounded awesome! Idled 6-7 minutes at 165 (yes, I put a 160 thermostat with two small drilled holes for the time being. Will switch back later)- I believe it could have sat there and idled all day long at 165. Shuts off and cranks up great at this point, when it's under 200 degrees. Anyone got any ideas? The carb base gasket is so thin for this square bore, it's laughable. Can't find a thick gasket for it anywhere. Could the gas be boiling? Would a thin phenolic spacer help keep the carb cooler? (Not much room there with that air cleaner, but would make it work, if it would help). Carburetor seems peppy and bog free. Thanks.


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## trues607 (Dec 15, 2012)

If you were to pull off the air cleaner can you hear the gas bubbling after you shut it off? It also could be vapor lock in the line.

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## 05GTO (Oct 6, 2004)

trues607 said:


> It also could be vapor lock in the line.


:agree

Make sure the fuel line is as far away from the exhaust as possible,


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## gjones (Oct 8, 2012)

*?*

Thanks 05 and trues607. No, it is absolutely silent after shutdown. And yes, I believe the line is far enough away from the exhaust- comes through the frame member a bit ahead of the manifold pipe, and has some wire loom insulation on it (not sure if that does anything for it though). '66 convertible, '71 455. Does this sound like a vapor issue, and if so would the phenolic spacer help keep the carb a tad cooler? Thanks.


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## trues607 (Dec 15, 2012)

I think anything to get the carburetor up off the intake would definitely help on keeping it cooler. Not too expensive to at least give it a try.

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## 05GTO (Oct 6, 2004)

If the fuel line is located in the frame and exits in front of the cross member I doubt you have a vapor lock problem,


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## trues607 (Dec 15, 2012)

I was just thinking if you have a stuck float in the carb after you shut the engine off. Does the fuel pressure drop when the car is off? I know if the floats are stuck they will fill the bowls and go down the intake and flood out the motor. Just another suggestion.

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## gjones (Oct 8, 2012)

Thankee, again. I am so close to being "there", I can taste it! I will get a $1.59 spacer, probably for about $19 and try it. Funny you should mention the float... just pulled it apart last night (for about the 10th time) and ditched those stupid spring loaded needles (had 2 sets of those) for some solid ones that came with the rebuild kit a while back-but of course didn't come with the retaining clips...SOO, I made some nice ones, and quadruple checked the specs. The old needles had a tendency to stick SHUT! NOW, even when the air horn overturned, I can lift the floats up and down, with positive action. MUCHO better! As far as pressure is concerned, I don't know- don't have a gauge, YET. I am going to redo the fuel lines up soon (at least from the carb to the mechanical pump) to a better setup with a gauge and such. Am only running a single line. Is this okay, or do these Pontiacs need a 2 line system?


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## Rukee (Feb 8, 2007)

Single line is fine. 
Also be sure to buy ethanol free gas.


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## geeteeohguy (Feb 2, 2008)

"_also be sure to buy ethanol free gas_." LOL!!! I wish! No such animal in the CA! And yes, the new fuels percolate and vapor lock very easily. One thing that can help is installing a vapor return system. They came stock on '66 and up GTO's with HD cooling and/or AC. And they _really_ work. I re-installed the oem one on my '67 GTO after i had removed it in ignorance 25 years earlier, and it fixed all of my 'fuel' problems, which included severe vapor lock.


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## Mr_Roboto (Apr 19, 2013)

Just a dumb question, is it possible your timing is giving you issues? Just asking. It's probably fuel, but it's another thing to check.


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