Help on Operation of Holley electric choke

[Dave Bilyk]

Guys, anyone understand the electric choke mechanism?
Trying to set up cold start / fast idle, but does not come off fast idle.
Any ideas what is wrong?

first what seems right.
The choke plate opens fine dont have an issue with that.
Before I start from cold I press once on the pedal, this gives a squirt from the accel jets, and also trips the fast idle mechanism so that the adjusting screw drops and the red plastic lever behind the choke thermal element pops up and locks in position.
I press the starter and the engine starts and runs about 2000rpm, I can adjust this speed with the fast idle screw no problem.

what seems wrong
So now the engine continues running at 2000 rpm, as the choke plate fully opens and continues to run at this. I have to push gently on the red plastic lever to release it so that the engine comes off fast idle. Engine then ticks over at 1000rpm.

thanks

 

[Jonathan Strain]

I believe that the choke relies on vacuum to take it off fast idle. Does your engine develope enough vacuum to operate the choke mechanism? Did the carb come with the choke or did you add it?

 

[Jac Mac]

Which idle screw are you adjusting ?- choke idle screw is part of the choke mechanism & quite hard to access.

Choke Bi-Metal spring cover has arrow with rich/lean marks- turn in 'lean' direction very slightly ( should be notch in plastic cover that lines up with register in choke bracket- this is nominal setting point ) move approx 1/8" from this & try it.

Jac Mac

 

[Pete]

Dave, per Jac Mac's post, loosen the three screws that hold the bimetal spring cover. You should be able to rotate the cap in either direction. Sometimes one of the screws has a set of teeth that might restrict movement. Simply take the teeth off. Now, rotate the cap clockwise to open. To set the butterfly to the best setting rotate the cap counterclockwise to the closed position. Only you don't want the butterfly closed tight against the airhorn. You want the butterfly to be closed so that you can push it open with very light pressure with your finger and it springs back to the closed position leaving about a 1/16 to an 1/8 gap. Now tighten the screws and that would be a good setting. sometimes the bimetal springs don't jive with the marks, or as the spring ages the marks will be off. Now when the engine warms up you should be able to tap the throttle lightly and it will kick off of fast idle. Hope this helps.
Pete

 

[Dave Bilyk]

Jonathan, engine runs fine, when I remove a vacuum tapping plug the engine dies, so I think the vacuum must be fine. The carb and choke were on the engine when I got the car.

Jacmac, yes the choke idle screw which is really hard to get at since it is behind the choke bimetal element.
I read in Holleys literature that turning the spring cover adjusts the time in which the choke plate opens, one way for sooner, the other for later, just havent tried it yet to see if it releases the fast idle too.

Pete, is this the normal practice? i.e. kick throttle fully down before starting to set fast idle, then once the engine is warm kick the throttle again to come off. I had assumed it would come off fast idle automatically.

thanks

 

[Steve C]

Dave,

Jac and Pete have it pegged and yes you need to kick the acceletator pedal or throttle in order to release the cam that has been set cold by your cold kick of the accelerator then the bimetal spring that has now expanded with engine warm up will work it's force and open the choke plate.

Steve

 

[Eric A.]

Dave,

Jac and Pete have it pegged and yes you need to kick the acceletator pedal or throttle in order to release the cam that has been set cold by your cold kick of the accelerator then the bimetal spring that has now expanded with engine warm up will work it's force and open the choke plate.

Steve

This is right. The fast idle cam relies on gravity to release. If the throttle isn't opened to let off the pressure of the screw against the cam it won't release on its own and allow the idle to return to normal. It is almost always necessary to tap the accelerator pedal to release the fast idle.

 

[Jac Mac]

Also make sure that the choke mechanism is not being fouled by a stray piece of base gasket or other impediment, doesnt take much to prevent it's non/return.

 

[Tony Hunt]

Dave,
Like all electric chokes - take it off completely.
This way, the carb can be set up properly for warm conditions and there's no risk of overfuelling.
The Holley has fat accelerator jets. 3 pumps on the throttle to the floor before firing up, and blipping the throttle when the engine fluffs during warm up, is more than enough.
My kids have no idea (not surprisingly, I suppose) of the workings of a conventional carb and are fascinated by the '40's starting procedure. They now fight for their turn to run the engine every month during the winter!
The electric choke is a concession to the unknowing American market and has no place on our cars.
Tony