whofarzed

A few weeks ago I popped off the cap that was on the mixture screw and adjusted my mixture. It was fine for a while but it slowly got worse. Today I had to adjust it about 2!/2 turns counter clockwise. as my car was almost stalling. If you do not put the mass cap (or whatever it is called) will it not hold the setting? I thought that my car was running rich because my plugs are all black, and a puff of black smoke sometimes comes out the exhaust when it backfires at high rmps. Also I am getting about 9mpg! One tank will get me less than 170km of city driving.

Doesn't turning the mixture screw counter clockwise make it even richer? Why will it idle better like this? Is my only solution a carb rebuild?

I tried setting the mixture like in the Haynes manuel. They say turn it all the way clockwise until the engine hunts, then turn it slightly counter clock wise. However, I can get it to idle like this for a while but after 10-15 sec the idle will drop and I have to press the throttle to jump it back up. Then it will be fine for a while, only to do the same thing after 10-25 sec. (Thanks and sorry for the long post)

hanman

A couple of things,
1. I don't have that cap on my mixture screw (80). It doesn't move by itself. If it did I would replace the spring, thats what holds it in place.
2. Your mixture screw should only be turned out about 2 to 21/2 turns from seated anyway. If you had to turn your out more than that I think you have other problems.
3. You should be able to turn the mixture screw in (clockwise) until the engine starts to misfire, then back out just a litte to smooth it out. Then adjust the idle screw, the one way over to the right, to get about a 750 rpm idle. IF you can't do this, you have other problems.
4. Other problems are: vacuum leak, ignition, plugs, etc.
5. By the way, an air/fuel mixture gauge sure makes the job easier.
hanman