On an 88 OMC 3L GM with a 2bbl Rochester carb, where do you connect a vacuum gauge? Is there a port with a screw-out plug on the carb base somewhere or do you connect it elsewhere?
there might be a plug in the throttle plate that has a allen hole in it. you could remove it then buy a barbed end and hook vaccum line to gauge. what are you trying to find out valve problem or idle air adj?
Actually it was just out of curiosity, in case i needed or had the inclination to check any of those things. Speaking of which, how is it used to set the idle air? I've been closing both needles, opening 1 turn and then alternately adjusting them to get the best idle. Is the vac gauge method better (easier)?
I've just always used a vacuum guage and tach to set up my carbs. Replaced my carb two nights ago and was looking to get it set up like I normally do. But it seemed to run real well out of the box so I figure I'll leave it until I can try t on a lake.
This is more for older cars etc, but you want to adjust the idle speed to spec and adjust the idle jets so you have the highest STEADY vacuum at the stated idle speed. As you adjust the jets, you ahve to keep adjusting the speed all while watching what the vacuum does. Gives nice smooth idle (assuming you didn't oveadvance it like I used to) and is more accurate than tuning by ear, but uses the same process.
