|
|
Posted by David Sherman on Tuesday, December 16, 2008 at 21:58:34 :
In Reply to: Re: Running problem under load posted by todd on Tuesday, December 16, 2008 at 20:21:27 :
Well, then maybe the vacuum advance is not advancing like it should. Normally when you check timing, you remove the vacuum advance hose from the distributor and plug the end of it with something. But to check the vacuum advance, first set up the timing light with the hose hooked up, and see that the timing advances noticeably when you open the throttle. I know exactly how far it should advance when the vacuum drops, but I know it's an amount that's very easy to see. The usual cause of a vacuum advance not working is a cracked diaphragm, which means not only do you not get the advance, but you get a vacuum leak which causes a rough idle. Another way to check for that is to "sniff" for it with a short piece of vacuum hose attached to a propane torch that has the burner removed, by blowing propane around everything connected to the vacuum system, you'll be able to find any leak. Wherever propane gets sucked in, the engine will speed up and smooth out.
Follow Ups: