Posted by Ricker on October 05, 2000 at 15:41:41:
In Reply to: Re: Vac. gauge usage?? posted by Thanks on October 05, 2000 at 13:40:45:
Not necessarily 230 specific (since I've never owned one!) but here is the steps to properly tune an engine:
Get it up to temp. Set the curb idle, then your timing. Now hook up a vacuum gauge to the manifold and a tach to the ignition. Start adjusting your idle mix screw until you achieve maximun vacuum, then back it out about 1/4-1/2 turn. You will now probably have to change your curb idle back to where it should be. Do the same for the other srew, if equipped.
Now, recheck your timing, as it will have changed a little. Keep your eye on the vacuum gauge as you want to maintain the highest possible reading. And if your idle is off a bit, you won't set your timing properly. These two things need to be in sync.
Once you're happy with your set up, take a drive (a hard one) and listen for pinging. If you have some, try retarding your timing just a bit and/or richening up your mix screws. Not too much, just enough to eliminate the pinging.
That's all there is to it!
But, if when you attach your vacuum gauge and you don't have a nice, steady needle, stop right there and find out why! You may have a valve problem, or other mechanical problems that will cause you to never get it tuned right until it's fixed.