The Stovebolt Site Forums The Shop Area Engine Shop Rochester B Throttle Shaft Leaking

The Rochester B on my '66 C-10's 250 is leaking air around the throttle shaft. When I pump the throttle, several drops of gas spray out around the shaft, and once its running, the idle smooths out when I put thumb over the end of the shaft. Is there a way that I can seal it off again?

I have a carb rebuild kit from LMC (had to replace the accelerator pump and bowl gasket). Would it have the part that I would need to seal it off again?

This weekend is the Food Lion Auto Fair at the Charlotte Motor Speedway and I may look for another carb there if it the leak isn't easily fixable. The throttle bore is 1-9/16" but what is the bolt spacing for a 250?

Thanks everyone!

Sounds like you have a classic case of a worn throttle body. You will have to take the throttle body to a machine shop and have them machine it, the insert the proper sized bushing to the throttle shaft. Or just get a carb that has a tight throttle body. Either one wouldn't cost too much I would think.

Thanks Apache, when I pump the throttle I can see the shaft jumping from about the 5 o'clock position to the 11 o'clock position. I called the machine shop that rebuilt my 250's head and they said that they don't work on carbs anymore. They did say that they know of a few places that still do, I'll have to call them back to get their names.

I haven't taken it apart yet and the '63 or '66 shop manuals don't show that part of the carb taken apart. I was hoping that there was an O-ring in there that I could swap out.

I'll keep my eyes open for a cheap Rochester B tomorrow when I'm strolling through the swap meet.

66stepside: I have a Rochester B on my '57 GMC and just recently found an online manual site with complete ddiagrams and procedures. Google 'rochester carbs' and click on 'rochester carbs' Scroll down to 'Rochester carburetor manual newage metal.com . Hope this helps.