Posted By: plumcrazycuda
Holly 650 double pumper trouble? - 06/03/13 12:04 AM
I just bought this carb and it is used but looks good. I put it on the car and it wants to run but can't get it to idle. I got a vac gauge and some how I am loosing vacuum when I get it down around 1k. anyone have any idea what is going on with the carb?
Posted By: plumcrazycuda
Re: Holly 650 double pumper trouble? - 06/03/13 01:06 AM
I figured it out. I had the large vacuum port unblocked.I Plugged it and it idles good now.
Posted By: tjmarcus1
Re: Holly 650 double pumper trouble? - 06/03/13 02:07 AM
I would have thought you could hear a huge vac leak?
Posted By: j.mcconnell
Re: Holly 650 double pumper trouble? - 06/03/13 02:31 AM
Any ideas on something other than the port being unblocked? I have a similar situation (bad, unsteady idle) and all of the ports on the baseplate are plugged. While measuring the vacuum at idle, I can unplug the gauge to create a vacuum leak and it doesn't make it idle any worse. Waved a propane torch and sprayed ether all over it with nothing really stood out
Posted By: ajcasini
Re: Holly 650 double pumper trouble? - 06/03/13 02:42 AM
How far open are the throttle blades? How many turns on 4 corner idle screws?
You may be too rich at idle and causing you to open throttle blades too far which is idling off the man circuit not the idle circuit.
Make sure your throttle blades are only open enough to make a square out of the transfer slots.
Posted By: MR_P_BODY
Re: Holly 650 double pumper trouble? - 06/03/13 02:51 AM
Whats your base timing at... make sure you have enough
timing first thing
Posted By: plumcrazycuda
Re: Holly 650 double pumper trouble? - 06/03/13 03:19 AM
With open headers I couldn't hear. As far as the timing I have 34 degrees at about 2800 rpm.I may have to jet it down some. The guy I bought it off of told me it was on a 440. It don't seem to be running rich but I was just happy to get a idle at this point!
Posted By: j.mcconnell
Re: Holly 650 double pumper trouble? - 06/03/13 03:24 AM
Saturday I removed the carb and squared up the transfer slots and set the idle screws at 1.25 turns out from all the way in. Initial timing was 15 degrees. The car would not idle like that. I had to screw in the idle speed screw about 4 turns to keep it alive. At that point I could still kill the engine by screwing in the idle mixture screws. I upped the initial timing to 20-22 degrees with no real improvement.
I have a lean burn distributor I was going to swap in but didn't have a rotor for it.