So it was running fine before with my Holley 1904 on and I wanted to put my new 1940 on. My distributor starting to go a little bad, loose bearing, but I don't think this would cause this since it was running fine with the 1904. I'm pretty sure it's not the loadomatic distributor since my 1904 doesn't have a spark valve and it runs fine. Any diagnostic of this would be appreciated.
Here's a bump for ya. What was the original application for the 1940? Try putting the 1904 back on and see if things get back to normal. -Dave
Th The 1904 works great on it. I switched it and everything was back to normal. The 1940 came off a 67 mustang 200 at the auto wreckers. It was professionally cleaned. While I put it back together. I got it running better but it's still not good. I fixed some of the vacuum leaks but I need the correct air mixture screw. I was using an edlbrock one but it caused a vacuum leak. I now have my 1904 one in it but it's not long enough so it runs real rich.
How does it sound if you bring the rpm up slowly? Kinda sounds like it isn't getting the pump shot while still having enough fuel to keep motor running, as if there are a couple things going on. Can you look inside it to see the accelerator pump squirting? Does the motor feel strong if you bring the rpm up slowly?
If I bring it up slowly it revs high. It's getting plenty of gas. Although if you hold it constant, the rpms aren't constant, up and down.
The rpms not being constant sounds like a vacuum leak. Could you look in to see the squiter, if you've taken it off it may still ave enough fuel to operate the squiter.
I'm thinking b/c I don't have the correct idle mixture screw that that could be a vacuum leak, right?
Yes. Most people think with mixture screw out that fuel will dribble out but in fact air get ****ed in and cause a vacuum leak, you made a good observation. I may have one the right screw. But it may not be all the vacuum problem, generally with air leaking around it the idle will be highish and rough. It sound slike you have more than one leak going on. Did you match the baseplate gaskets? I know those little 1bbls have some odd gasket stuff going on, they have vacuum p***ages that run from the intake flange all the way to the top of the carb, 1904's have them and the 1940 may not so that the p***age may be open. Just something to check.
Thanks, I learned that gas doesn't come out when I backed it out too far and it fell out. haha. The throttle body has cuts in it so air can get into the p***ageways it needs to on the bottom. For my 1904 i had to cut a whole for the gasket but it doesn't look like that's the case for the 1940. If you've got a screw that'd be great. I'm looking at a screw on Mike's Carburetors http://www.carburetor-parts.com/Carter-BBD-Thermoquad-Holley-Idle-Mixture-Screws_p_399.html and http://www.carburetor-parts.com/Holley-1946-Idle-Mixture-Screw_p_1986.html What do you think?
Might be your best shot, that 2nd one. I checked my stuff and have plenty for the 1904 and one for the 1920 but don't know if the 1920 is the same as yours. I'd be happy to send you if you think it'll work, pm your address and its' on it way.
I think the 1920 and 1904 ones are similar, I know roughly the 1940 has to be longer. I'm gonna try NAPA then maybe Mike's Carburetors.
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