Runs like, hell. Got me stumped HELP!

[Clyde's Keeper]

While on A trip, engine freeks out, appers to have gone lean. Huge flat spot off idle, popping through the exhaust very low on low end power. Remove the plugs and found the cylinder fed by the right or upper part of the duel plane manifold were distinctly cleaner than the other four. The #1 plug so clean, appears to not be getting fuel. The other four are black/sooty, running too rich. Checked intake bolts, removed carb, checked and adjusted back to base settings, installed new plugs. Runs marginally better but mostly the same. After short test drive, still appears the #1 plug not getting fuel or at least not very much. 2 and 3 and black, 4 is less black. Have not pulled the other side again. Checked for vacuum leaks with some carb cleaner. Nothing noted around the carburetor but did have some odd changes in the idle but unable to pinpoint and leak when checking the manifold. I still suspect a vacuum leak. I find the front idle screw is just off the stop and the engine is going around 900 rpms. Engine will not stall when closed, I am pretty sure I used to be able to get is to idle as low as 700 and even stall if backed off all of the way. I'm stumped. Help! I got fun places to go in the this weekend!

Thanks,

r

[Norm B]

Does the engine miss fire? Have you tried removing the #1 plug wire and running it to see if there is any difference? Try spraying carb cleaner where the intake plenum for #1 meets the cylinder head, maybe you have a bad intake gasket. As a last resort, I would check for intake valve travel on that cylinder. That's all the suggestions I've got. These type of problems are a real pain. Good Luck.

Norm

[Brian Z]

302? Carburated? It could be a clogged fuel filter, air filter, clogged carburator? Ignition problem? Did the plugs look ok?

[skullandbones]

r,

Brian Z. hit it on the head. It's one of those things!!! Problem is focusing in on the right one. Your roadster was running fine, right? Then suddenly something changed. I would check for spark on a couple of plugs on both banks. Then you can make sure it isn't something like a coil going bad or a cracked distributor cap (check rotor and other things electrical). After that, you should check to see if you are getting a good squirt of gas from the nozzles from the accelerator pump (more than once). If you have a hole or tear that could really cause some issues. Make sure there is no question in your mind before going on to the next possible factor. If you think there is any chance of gas contamination, you may need to disconnect the fuel filter and run some gas into a glass container and examine (particulates or water). Worst case scenario is you will have to disassemble the carb and see what's going on. It is possible you have a clog from particulates. I once had a motorcycle stop on me over and over again until we discovered bacterial contamination in the bowls. Yes, there are bacteria that will grow in gas (Puedamonas of some specie). So don't assume anything until you know from observation. Good luck. WEK.