Originally Posted by killerformula
I've had a couple of issues with my Holley for quite some time now, and have really just now gotten around to addressing them. Being that its cold out this way, I'd like to be able to use my (Manual) choke, but it's never given me anything but grief. At a certain point it the linkage travel, it will raise idle and and keep me from having to feather the motor, but it will still die if I try to put it in gear. Any more travel and the motor just loads up, lots of black smoke and chokes itself out. So my only solution is to sit there feathering the thing for probably a good 5-10 minutes until it wants to run.
I have a relatively big cam, 280h comps in a 383. I wonder if I'm dropping so much vacuum that the power valve is dumping during choke? I just rebuilt the carb, so everything is nice and fresh. Really didn't even need it, but this problem has preceded the rebuild.
The other minor issue is that there is a tiny fuel leak which I think is coming from the rear bowl. It doesn't leak while the car is running, but after its off and sits for 30 min to an hour, a very small pool of gas builds up on the passenger side intake, right under the choke linkage. The leak is so slight its almost impossible to trace. The carb gasket is moist only from the point of the leak or so to the back of the carb, not on the front, which makes me think it must be coming from the rear bowl.
Any ideas are appreciated, thanks guys.
Agree that heat is likely causing the fuel percolation, causing it to pool on the throttle blades than seep out past the shaft.
Agree also on using an insulator of some sort, but don't unnecessarily lower the float level. This will delay actuation of the various carb circuits.
Be sure the idle mixture screws are adjusted to give the highest idle speed or highest vacuum reading, w/the engine fully warmed up- like after a 15 minute drive.
As for the choke, you need to readjust the fast idle screw so it'll raise the idle more w/o needing to close the choke more. This will keep the engine from loading up from too much choke and will hopefully allow it to go into gear w/o stalling. BUT, there's also a possibility that it's just going to take longer to warm up. You are using a thermostat, right? No 'stat makes the warm up take a lot longer than it should.
Another thing that can help cold drive-off is to give it enough initial timing. If you add initial you'll need to take out some mechanical advance to compensate, otherwise the total timing will be too high.
If you're using ported vacuum for the vacuum advance, switching it to manifold vacuum (and resetting the idle speed and idle mixture screws) can help. In this case the initial and total timing does not need to be changed.
If you're not using a vacuum advance, you should seriously consider using it.