The Stovebolt Site Forums The Shop Area Engine Shop carb

Just did a search, and didn't find what I have seen before, I have the Rochester B 1bl carb, and it starts and runs good, but seems that it's running a little rich..Looked in my manual, and it was saying to turn in the adjustment, and back out 1 1/2 -2 1/2 turns..Really don't want to do that..My question..should I turn it in until it starts to stall, and back it off, or should I turn it until I get the best idle speed? Thanks

are you speaking of the idle on the carb? because you stated you did not want to mess with,,,, if it is running like you want it to I would not mess with it, I did increase my idle about 250 rpm to about 800, seems to like it better their,,go google for this site ,Recarbco, I have trouble with the copy and paste,,,it is a good site with a lot of good carb tips. I got mine re-done by them about 2yrs ago,,see ya........Fred

Thanks Fred..Already went outside and messed with it..Have adjusted idle speed before, and usually keep mine about 800rpm, but was messing with the air/fuel adjustment, because it seemed like it was running a little rich..Hope I didn't screw it up, but seems to be running OK..Guess it's time for a test drive..Later, Steve

You run the fuel/air screw in till it stops then back it out 1 1/2 turns then start the engine and turn the screw in and out about 1/2 turn at a time to get the best idle then leave it alone.

Thanks V6, that's what I need to know, Steve

I adjust it by turning it in slowly till the engine starts to slow down than back it out till it smooths out usually about 1/2 turn. That is the idle mixture. if it is too rich running down the road check the float level. You may have to go to a leaner main jet. On my 235 I run a .055 jet. It had a .053 but was a little lean.

Thanks, it runs good, but the exhaust pipe is black, and it smells rich..The carb is a bebuilt and have never had a problem, just wanted to save a little mpg..Steve

My exhaust is a little sooty too. I'm running a .054 Jet. I'm in the Mile High City so should I put a leaner jet it it. Shooper, do you know what jet size your running? What's the altitude there? That may be a factor.

There are other things that can go wrong inside that carb. Running rich will carbon up your valves and you don't want that. There is a power piston inside that allows more fuel flow when the throttle opens and the vacuum is lowered. If that hangs up, you can have a rich mixture problem.