Quote:
Originally Posted by scicala
It sounds like your pretty sure there are no issues with the Load-O-Matic ignition and you are getting correct spark advance.
I have been doing these Holley 4000's (and 2140's) since around 1968
and have learned quite a bit about them. If you are getting a stumble from too much accelerator pump shot, them a breif shot of black smoke out of the tailpipe should be visible when this happens. It's more than likely not enough pump shot causing the hesitation/stumble. With the engine off, and holding the two choke plates wide open, try to look inside and locate the two little brass nozzles where the accel pump shot comes out of. You may even need a mirror. Kind of hard to see with the carb installed. They are short tubes on an angle. You should be able to see a shot of fuel come out of each with the slightest movement of the primary throttle lever. It's possible Pony Carbs installed the pump piston too high (parts from other carbs can do this), and the piston is above the point of sealing the pump bore. This will at least give you a starting point to know what you have now. Wish I was closer to help you out. I've sold these on EBAY and take the time to do them correctly. Never had any complaints. It is arguably the most difficult carb to assemble and assemble correctly. There is a difference between just cleaning and re-assembling with new parts and doing it correctly. Sal Cicala (313) 805-0159.
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I was so close on getting this thing to run well that I was hoping the very slight stumble might be the result of the accelerator pump. HOWEVER... The distributor certainly appears to be an issue. We had to replace the vacuum advance double diaphragm assembly and that seemed to fix the lack of advance. A buddy of mine set the timing and I drove it home. It ran progressively worse as I drove it. I put a light on it and it was about 20 degrees retarded. I reset the timing and it ran very well with just the slightest stumble and a slight ping.
Today I drove the car back and forth to work and again it seemed to get a bit worse. I started to experience heavier pinging. Decided to put the light on it again and take out a little more timing. The light showed it to be about 20 degrees advanced. Talked to my buddy and he told me that the same thing happened to him. He set it once and then checked it again later on and the timing had shifted about 20 degrees.
Two questions... What the heck would do this? And the vacuum lines... Normally you disconnect and block when setting the timing... What do you do with the Load O Matic? Do you disconnect both?