Hi all I have a 69 427 tri power, I had the carbs rebuilt a few months ago (by a carb professional) but cant seem to get them to run right. When I drive around town the car runs fine but over 4000rpm on the highway it seems to struggle for fuel and splatters then takes off like a rocket.
When I adjust the float level higher on the end carbs to allow more fuel it runs heaps better but the next morning after the car has been sitting fuel leaks from the bottom gasket of the two end carbs and stinks up the garage, I don't know a lot about these carbs which is why I had them completely rebuilt by a pro.
Am I overlooking something or is there something wrong with the rebuild any advice would be much appreciated I have tried everything I know
Cheers

 

Tighten the bowl screws and they'll quit leaking.

 

Adjust accelerator pumps? On my King Demon 1190 (in boat) solved my momentary hesitation problem. Just a guess, and this will get it to the top, Mark

 

Thanks guys all the carb screws are tight not sure how to adjust pumps ill do some research thanks Mark

 

Sounds like one or more of the carbs is running lean, but float level might not be the root cause. I wouldn't touch anything without first talking to the guy who did the work.

 

A couple things to look at (and by carb professional, I hope it is someone old with experience with this unique tri-power setup, otherwise you are asking for trouble).

1. check your fuel pump. at normal highway speeds, the end carbs should not even be opening. you may very well have a fuel delivery (volume) problem that can't keep up. raising the float level is just asking for trouble and dumping fuel. not good. (in fact, the end carbs should be set to the low end of the float level range, not the high end).

2. ensure the rebuilder did not make a mistake on the springs for the vacuum pods. The end carbs open via vacuum from the center carb, not mechanically, too light spring could be opening them too soon but it's less likely.

3. make sure the end carbs have correct jetting. most documentation is incorrect or misleading on the jet size. you want .076" which is a #70 jet, NOT a #76 jet, but again this would be more of the opposite (too rich) problem.

4. power valve could be bad. generally a 6.5 is recommended. may not be enriching under proper vacuum.

most peoples troubles with the tri-power are related to idle, not running out of fuel, so I strongly recommend checking the fuel pump/tank screen collapse before you start tearing into the carbs...

 

If they are leaking take them back to the rebuilder, and have him look at them on the car if possible. He may even be able to tune them for you if he has the car.

 

Thanks for the feedback guys, I did replace fuel pump and filter I have eliminated ever thing I can do I will give the car to the carb guy and let you know what the problem was thanks for all your help
Cheers