Hello friends!,
Where can i connect the vacuum-tester?(on the intake manifold or carburator).
I think i have a vacuum leak somewhere in the system,what are the numbers to read on this vacuum-tester?
How can you tune your carburator with a vacuum-tester?
How can you use a compression tester? :confused:

Thanks a lot!!!!!!!! graemlins/beers.gif
EDDY merlin.

You can plug the vacuum gauge into a port on the intake manifold, or to a full time vacuum port on the carb. (Not all of the vacuum ports on the carb have vacuum with the throttle closed). You are looking for a 18-21" h.g. with a stock engine when idling. If you have a non stock camshaft the numbers will be lower. The important thing is that the needle is steady. If not, you have a problem with one or more cylinders. Retarded timing will also give you a low, but steady reading.

To adjust your carb with a vacuum gauge, adjust idle speed, then the idle mixture screw on each side till you get the highest steady vacuum. That is the easy way.

I like to start out with two initial turns out on each idle mixture screw, turn out a little more to see if the vacuum will increase. Then I turn in about 1/8 of a turn at a time until the vacuum just starts to drop significantly. Then I turn back out out 1/4 turn. Repeat for the other idle mixture screw. Both should end up being pretty close. Either way, readust your idle speed when you are done.

For the compression gauge, use it on a hot engine. Remove all your plugs, disconnect the ignition, and block the choke and throttle wide open. Insert gauge, crank till the gauge stops climbing. Don't forget to unblock throttle when you are done. Lowest cylinder should be at least 75% of the highest.

First you MUST be sure your timing is RIGHT ON before attempting to tune the carb. The vacuum-tester is attached to a vacuum line off the carb or intake and you watch the gage as you turn the air-fuel mixture screw in till the vacuum drops then turn the screw out till you reach maximum vacuum then go to the other screw and run it in till the vacuum drops then back out again till you get maximum vacuum. This should help, its been a while since I set the carb up this way so you may want to try adjusting twice to see if you can make it any better, probably not but you can play with the adjustments till your satisfied.


Tazz

Thanks a lot guys!!!!!!!!
I'll check this out!! graemlins/thumbsup.gif

EDDY merlin.

Excellent post.....I think I can finally tune my carb now. graemlins/thumbsup.gif