Hi All,

I have a quick question, when the car cools down after a drive, my electric choke closes a little bit after an hour or so and I when I go to start the car it idles higher (200 rpm more) than my normal idle speed and stays there once the choke is open. Once I tap the accelerator it drops back down to normal.

Note I have a Holley anti diesel solenoid that requires the throttle to be depressed slightly before starting.

Is this resulting in the last step of the fast idle being engaged? Or is something else hanging up?

 

If the choke is closing, odds are the fast idle cam is what's holding your idle speed up- you can back the choke off a little by loosening the three screws and turning the black cover so the choke opens. Not too much or you can make the choke not work at all. Other option is the screw from the throttle shaft to the fast idle cam.

 

Tim is right. And another tip is to take some Gumout Carb spray cleaner and wash months of grime off both sides of the carb. Wait a few minutes, then follow up with a shot of WD40 on anything that moves. You would be surprised how it improves some carb issues.


Hey Gumout,
Still waiting on my endorsement check. Is it in the mail?

 

I rebuilt my Holley 750 3310-4. Did not have an anti-diesel solenoid. My lawn tractor does ....

Turning the body of the choke affects how long it takes to open.

Cold and after sitting a while I give mine three 'to the floor' pumps. Ideally the first pump sets the red plastic arm for the fast idle. It'll idle at about 1200, then drop down slightly after about 4 minutes.I think there's a high and low little notch or bump.When I tap the throttle it drops back down to normal idle.

That red plastic arm is a p.i.t.a sometimes. Yes dirt and gunk can make it stick. Mine was just slightly cocked and didn't take more than finger pressure to straighten it out. I use a mirror and a really skinny screwdriver to adjust the set screw. Get a mirror and see what its doing.

 

Should the choke be able to close 100% when cold?
I have a Holley with the Holley electric choke set-up, and when adjusted to the "coldest" setting, the choke flapper will only close up to leaving about an 1/8-1/4" gap - not fully closed.
I noticed this due to my fast idle not getting set to the highest setting when cold.
All this adds to rough start on these chilly fall mornings.
I removed the spring/cover from the choke controls, and the little lever that sets the choke level doesn't travel far enough to close the flapper fully (or set the high idle cam on the highest setting). So, it's not the coil spring adjustment issue.
Then I thought maybe my choke valve rod/arm needed adjusting - so I broke it! (Doh!).
Waiting on a new one to arrive, but trying to educumacate myself before parts arrive.
I also ordered a new fast idle cam, since the existing one looked a little worn in the "teeth" area, so maybe it was getting hung up on the high idle set screw.

 

Yes. When the engine and carb is cold, the choke should snap fully closed when the throttle lever is cracked open. Once the engine starts, the pulloff system should crack the choke open about 1/4".

Lars

 

Thanks Lars, That's what I thought.
So, one of 2 things is holding mine from closing fully:
1) The travel in the internal lever of the electric choke mechanism isn't traveling fully, or
2) The flapper valve connecting rod is not the correct length, so it's not translating the full stroke up from the lever in #1, up to the flapper.

If I disconnect the rod from the electric choke, I can easily get the flapper to shut fully, so it's not internal to the carb.
The Holley Choke mech has some kind of vent valve that affects the travel of that little lever (yellow arrow), and it has a set screw on the outside of it (black arrow), but that just looks like an mechanical end-stop and maybe an air adjustment (?), What is the purpose of that part of the mechanism? Nothing about it in the instructions.

When I have the choke attached to the carb with the spring and cover off, and with the flapper rod connected, I can actuate using that internal lever, but it will only go to the "almost shut" position, which also falls just short of setting the fast idle cam to its highest notch.

Thanks,

 

The piston is the choke pulloff - it cracks the choke slightly open upon cold-start to allow the engine to run. It is vacuum operated through a vacuum transfer passage between the carb main body and the choke housing.

Sounds like one of your linkage pieces has been bent or altered if you don't have enough travel. range to allow the choke to fully close.

Lars

 

Hey Lars - Just to close the loop on this one.

I ended up ordering new a kit of choke rods and a replacement fast idle cam which all arrived yesterday.
Rebuilt the choke/carb connection with these new parts and still had the same issue - I even tried using another of the 3 different rods that came with the kit but to no avail.

Got on the phone with Holley Tech Support - and (as usually is the case), I was able to detect the problem as I was talking through the issue with "Anthony" on the phone.
Turns out, that "Choke pulloff" piston you referred to above, and noted by the yellow arrow in my photo, was sticking.
There's a ball fitting on the end of that tiny wire that fits behind the cylinder seal and seals off when the ball is fully against that upper seat (choke in full closed position).
Well - it wasn't able to travel fully to get seated - I shot some carb cleaner inside and let it drain from the set screw hole. Did a little forcing after that, and got the piston to free-up.
Now the ball seats fully inside - AND - the metal lever can rotate fully counter-clockwise, allowing the choke to fully close and the fast idle cam to set at the highest setting.
Hopefully I didn't damage anything inside that cylinder, but Anthony assured me that I could request a new choke body if it still has problems.
One for the memory banks (at least for me).
Thanks for the help!

 

You can pull the piston completely out of the bore to clean the piston, it's parts, and the bore. I always do it during any Holley rebuild.
Lars

 

Hey Lars - One more question:
What's the procedure for opening up that cylinder?
There's a pressed-in cap on the outside end of it, and the inside end cap (with the pass-though hole) looks like it's installed from the other end.
Do you pry off the outside cap?