Running a 364 Buick Nailhead with 3 Rochester setup on an Offy intake. When I step on the gas the car falls on it's face and/or stalls immediately. I can only take off by pumping/feathering the pedal. Once it gets going it also hesitate near the top end of each gear. I've been told it's lacking fuel, I've been told it's lacking air, I took it to a "hot rod" shop that kept it for a week and it's still doing the same thing. I'm by no means a mechanic and looking for help. Any suggestions would be greatly appreciated...
As far as the stalling problem goes, make sure the accelerator pumps are working correctly on all three carbs. Hesitation at top end could be a fuel delivery problem. Bad or inadequate fuel pump, too small of a fuel line, restrictive filter, bad or loose rubber hose upstream of the fuel pump causing air to be sucked into the system, just to name a few.
Progressive linkage? Most of the "fuel" related problems are caused by ignition problems. 1. Check and make sure your vacuum advance and mechanical advance are working correctly ie: full advance in by 2500 RPM, vacuum advance hooked to MANIFOLD vacuum and working (use a timing light) 2. On the bigger engines I have had to drill out the accelerator pump nozzles on the center carb to keep them from hesitating. 3. alky based gases will play havoc with rubber pump seals. Are you using alky resistant pump seals?
From the picture it doesn't look like progressive linkage. It might be a case of to much to soon. Looking at the end carbs I don't see Idle screws . If these carbs don't have idle circuts the engine needs some RPM before they come into play.
It does sound like an accelerator pump issue. Either too big of a shot or no shot at all. Alcohol in the gas tends to eat some types of accelerator pumps so I would definitely check it out. Does it idle okay? Just FYI - I'm no expert, but in general when troubleshooting a 3 deuce setup I like to remove and block off the two end carbs and see if I can get it running right on just the center carb. When you're dealing with so many possible factors you could end up chasing your tail. After it's running right on the center carb I start adding the other carbs back in, making sure the butterflies on the secondary carbs are sealing tight and there are no vacuum leaks.
From the picture it looks like it does indeed have the proper progressive linkage. As stated, I'd run it off the center carb and start from there.
The bell cranks on the end carbs will need to be shorter than the center carb so they can catch up when started later. They don't look like that to me. If they are all the same and it's progressive the end carbs will never get fully open.
Do a search on this site. There are a bunch of threads on this. Use search terms like: 3x2, 3 deuces, tripower, tri-power, etc. You'll find a lot of info, although not all of it is accurate, IMHO.
The Jalopy Journal
