tomtaz1975 wrote on 07/08/09 at 15:20:16:Not to hijack the thread, but I have been having the EXACT same problem...I think. No matter how I warm her up, I have to give her gas at idle just to keep her running when at a stop sign or red light, even with idle set high.
I did get a raptor but haven't installed it yet. I can't find the thread/help that shows how to deactivate the vacuum hose. Can anyone help me find that thread showing what to do with the hose?
OK, passing forward my new found, brilliant insights...
Of course, install your Raptor if you want and see if that's a fix. In the meantime, as above, you might try running with petcock set to PRI. If that solves your problem, you do have the same situation and either the vacuum hose or petcock are bad. Also, check the vacuum hose after operation for gasoline in it. It might not be much, I used a taste test (yechh!). That means leaky diaphragm in petcock, which is apparently unfixable.
If that doesn't prove a problem in this area then you're back to square one on diagnosis. Clogs in the petcock still might be an option, but not any more obvious than many other things that someone smarter can talk about. The vacuum problem is ruled out, because PRI is not vacuum operated.
The vacuum hose is mostly discussed only in passing. It is the smaller one running from petcock to a port on the carb on the opposite (right) side. Many deactivation methods are proposed. I removed it and used rubber caps from parts store under $2 a half dozen. Some say they will rot. Or cut the hose and clamp it. Or cut the hose and seal with a screw and some gasket sealer. Or I think some have put said screw seal right in the ports. Anyway, the carb's vacuum port must be sealed if not used.
If vacuum deactivated (you may know this) you run on PRI, and turn to FUEL (which is now OFF) when engine is off.
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