Re: '41 super 8 stumbles on idle

Posted by Dan Marrin On 2012/3/19 15:18:36

Dave:

Thanks for the idle adjustment tutorial. I just returned from partial carb disassembly, enough to get at the float, needle and seat. The float appears to be fine, no apparent nicks or dents, and appears to be hollow when shaken; I assume it floats, but didn't test that. I figure if it was leaking there would be some liquid inside, right? I adjusted it to sit at exactly 5/32" below the top as is speced for the Carter WDO 531 SA carb.

The needle and seat appeared to the naked eye to be ok, and seemed to be effective at stopping air that I blew into the inlet, while lifting the needle into the seat ever so gently. The needle appears to have some sort of hard rubber tip that goes into the seat. Is this kosher? All ther other needles I have seen appeared to be solid brass.

I also tested the fuel line pressure to the carb inlet with just the electric fuel pump running and it measured 3.5 psi after going through a pressure regulator. I didnt have a "t" availible to test it while running in tandem with the mechanical fuel pump; should I do this before going any further, to rule out excessive fuel pressure as a cause?

Since everything appeared to be fine, I reassembled only to find that I still have gas dripping into the throat at idle. Does this mean I should order a new needle and seat, and, if so, where might be the best source for a set that would meet the specs for this carb?