Holley Choke Question

snowgoer · #1 (**permalink**) 03-20-2011, 08:56 AM

I have a brand new Ford Racing 392 with a Holley SA (I think 750) with vacuum secondary. Since I got it 35 miles ago it has had a stumble when you accelerate. Yesterday it would not start so I took off the air clearner. I noticed the choke was open about 1/4 inch, engine was cold, and it would not close all the way, even after pulling on throttle. I moved the electric choke a little to the left, which should close it more, and now it snaps closed when yopu tap the throttle. The question I have is as it cools down the choke still only closes to 1/4 short of completely closed. I hit the throttle once and it snaps closed now. It seems the the red fast idle arm may be keeping it from closing all the way. Is this correct?

Good news is when I moved the electric choke to the left (Counterclockwise) the stumble is completely gone. I can't wait to drive it like this now as it seems to really accelerate quickly.

snowgoer · #2 (**permalink**) 03-20-2011, 10:19 AM

Actually do not know if choke is working at all as I warmed it up and the choke still only stays open 1/4 inch. Also checked hot wire going into electric choke and not getting and volt readings with the key on. Checked fuse and it is OK. Am I correct in thinking the choke should be fully open when warmed up and idling, or does it just open when accelerating? Thanks, Scott

snowgoer · #3 (**permalink**) 03-20-2011, 11:31 AM

OK the choke not opening was due to a blown fuse although it was in the fuse location marked "CL/HAZ" which I though stood for clock and hazards. Not sure if that is the correct place for fuse for electric choke especially when there is a choke slot marked. Well, with that fixed the stumbling came back. I am going to have to read more or looking for help on next steps to eliminate the stumbling under quick throttle action. I tried the chock in several places but stumbling still there. Any suggestions??

Jerry Clayton · #4 (**permalink**) 03-20-2011, 11:32 AM

Scott

Did you disconnect the wire before checking for voltage?

Jerry

snowgoer · #5 (**permalink**) 03-20-2011, 11:40 AM

Quote:

Originally Posted by Jerry Clayton

Scott

Did you disconnect the wire before checking for voltage?

Jerry

I did it both ways and it reads 12.6 volts

patrickt · #6 (**permalink**) 03-20-2011, 12:42 PM

You might consider just removing the choke assembly on the side and using a zip tie to hold the butterfly valve firmly in the open position. While my Holley is a manual choke, both manual and electric chokes are basically the same if you're removing them. Here's a shot with the yellow arrow pointing to the two zip ties that hold the valve open.

snowgoer · #7 (**permalink**) 03-20-2011, 02:26 PM

Quote:

Originally Posted by patrickt

You might consider just removing the choke assembly on the side and using a zip tie to hold the butterfly valve firmly in the open position. While my Holley is a manual choke, both manual and electric chokes are basically the same if you're removing them. Here's a shot with the yellow arrow pointing to the two zip ties that hold the valve open.

Thanks but I have the choke situation fixed as it was a blown fuse. Just looking for advise on the stumbling when I hit the throttle. I was thinking a bigger fuel nozzle.

jhv48 · #8 (**permalink**) 03-20-2011, 02:35 PM

Open your idle air screws another half turn and test before you start replacing things.

Gaz64 · #9 (**permalink**) 09-27-2011, 01:06 PM

Quote:

Originally Posted by snowgoer

I have a brand new Ford Racing 392 with a Holley SA (I think 750) with vacuum secondary. Since I got it 35 miles ago it has had a stumble when you accelerate. Yesterday it would not start so I took off the air clearner. I noticed the choke was open about 1/4 inch, engine was cold, and it would not close all the way, even after pulling on throttle. I moved the electric choke a little to the left, which should close it more, and now it snaps closed when yopu tap the throttle. The question I have is as it cools down the choke still only closes to 1/4 short of completely closed. I hit the throttle once and it snaps closed now. It seems the the red fast idle arm may be keeping it from closing all the way. Is this correct?

Good news is when I moved the electric choke to the left (Counterclockwise) the stumble is completely gone. I can't wait to drive it like this now as it seems to really accelerate quickly.

That's correct, all automatic chokes run a stepped cam for fast idle speed.

ReMorton · #10 (**permalink**) 09-28-2011, 04:38 PM

..I can't comment on the automatic choke issue, but I had a number of issues to resolve with SPO2089 after purchase. One was the hesitation on acceleration. I have the 393 crate/750 Holley like you. Basically a no mans land between 1000 and 1300 rpm. One session on the dyno indicated it was not the carb but the vacc advance. It was plugged and the dizzy was converted to full mech advance. Fixed 95% of problem. Next fix was throttle linkage. I adjusted it so that I had a bit more pedal movement from idle to normal operating. Problem's gone. Next step is to junk the Holley altogether.