# Early Tri-Power questions



## Lil GTO (Jun 27, 2006)

My dad has a 1959 Bonneville with Tri-Power, not sure how similar or different that is to the earliest Tri-Power setups used on GTOs. It is NOT the same as I have in my '64 GTO, but then, I don't think any part of my power train is actually from a 1964. 

It has a rather complicated vacuum linkage setup. He recently had the master brake cylinder and booster replaced/rebuilt as the booster was half full of brake fluid. On the way home from that, the car stalled a number of times and he barely made it home. Now, it will fire up, but with various throttle positions it will not continue to run. 

Earlier this year we replaced some of the rubber fuel hoses and fuel filter and it was running very well after that. 

So it would seem that either, the brake shop reattached (or didn't reattach) something in the vacuum system properly - OR - (and I think more likely) when he last had the carbs tuned, the adjustment was made to (unknowingly) compensate for the brake booster not acting properly in the balance of the vacuum system. Now that the brake booster is using the correct amount of vacuum - the carbs need to be adjusted accordingly. But even my mechanical linkage is a bit of a mystery to me. 

What is happening at the moment is that even with full throttle, the center crab's butterfly is not budging at all, it is free to move, but nothing in the setup is acting on it. I tried adjusting the device on the opposite side, but that acts to hold it closed not open, and I believe is related to temperature so shouldn't come into play when the engine is cold.

I suspect the adjustment that needs to occur is near the center of the photo, where it says Vacuum Switch, since the Vacuum Actuating Lever is the only thing that appears to be directly acting on the Choke Lockout Lever which is directly connected to the butterfly. 

There are a number of places which look like they would be good places to attach a spring, which might have been lost, but none of them appear to have any wear as if a spring was there for the past 60 years and recently came off, nor do any of them appear to be in a relative position where adding a spring would actually make any difference. 

I will probably stop over there later today just to see if that vacuum switch can be moved and if doing so affects the butterfly. 









If there are any Tri-Power experts out there who might be able to help - I can get some photos and even video of his actual setup. 

He would like to get it working again before the weather turns so he can move it to the storage facility without a tow truck.


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## Old Man Taylor (May 9, 2011)

I may be misunderstanding your description, but it sounds like the throttle shaft is broken. Manually activate the lever on the center carburetor to open the butterflies. Look down the throat of the carb and see if the butterflies move along with the lever. If not then the shaft is broken. The vacuum linkage doesn't have anything to do with the center carb.

Another thing that is common is for the lever to get loose. It is attached to the throttle shaft with a peened over protrusion from the throttle shaft. Over time this gets loose. You can use a punch and tap it to tighten it up somewhat, but that's a band-aid. That's when I would buy a new shaft and replace the old one.

I hope I'm making sense, my words seem to be garbled this morning.


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## Lil GTO (Jun 27, 2006)

The butterfly is moving with the lever and large assembly connected to the pedal is rotating - but there doesn't seem to be anything directly connecting the parts which one with the pedal and the part that moves with the butterfly. He's not home right now but I'll see if I can get a short video and post it.


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## Lil GTO (Jun 27, 2006)

The guy who last tuned up the tri-power a d who more recently solved a pinhole leak in a head gasket is going to stop by on Wednesday and look at it. 
the guy only works on Rolls Royce and ‘59 Bonnevilles. Rolls because he makes money doing it and ‘59 Bonnies because he has one.


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## Lil GTO (Jun 27, 2006)

He came and did his diagnostic. 
may the moment the suspects are the accelerator pump and or the internal gasket. 
he took the center card home to rebuild it.


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## Lil GTO (Jun 27, 2006)

One clarification - when I said the butterfly was not moving - that was in fact the choke plate that was not moving, and when cold, it should not be moving. The throttle butterfly valve was working fine. 

There is a very detailed video series on YouTube that walks through disassembly and reassembly by Vintage Speed. 

Center carb













Secondary carb


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## Lil GTO (Jun 27, 2006)

So the guy came back with the repaired center carb - assured us that it was the actuator pump - and it did the same thing. So he took off the fuel pump (even though it was clearly providing fuel at the top of the engine. He ran out of time and left it with no center carb and no fuel pump and said he has an open bay in his shop this week so bring it on out. Which of course means a tow truck. Dad has Haggerty insurance on it - and within 20 mile is free - but the shop is 28 miles away - so $30. Truck was supposed to arrive at 8 am - after a few phone calls the second truck actually showed up around 11:30 - so it is now on its way to the shop so the guy can fiddle with it all he wants until its fixed.


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## Lil GTO (Jun 27, 2006)

So the guy came back with the rebuilt carb and that did not fix the problem.
he took off the fuel pump and checked it and that did not solve the problem.
he decided it would be easier to work on at his shop. 
he cut open the fuel filter, not the problem.
he checked the compression, not the problem. 
turns out the issue was the points were failing. 
he also adjusted the timing and something else I forget and now it runs better than it has in years. 
not that it didn’t need other stuff but the latest bill, including house calls, was $1400 for a $15 part. And just in time to put it away for the winter. 
Next year he should be good since over the past couple years he has had a lot of stuff done, wheels straightened and painted, new tires, head gaskets replaced, brake master and booster repaired, center carb now rebuilt, new plugs and points (maybe wires as well, he didn’t say). 
if he finally gets the small hole in the exhaust fixed and the sportable radio working, it will be the best summer yet.


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