Hot Rods Holley carb

I have a sbf that was originally a smogger. Took all that stuff off and replaced the carb with a Holley 650. Runs way better now, however when it is fully warmed up something weird happens. When I shut if off and restart within a couple of minutes it revs very high and I can go down the road about 35-40 mph without touching the gas pedal. After about five minutes of driving it settles back down. It kind of feels like the choke has reactivated or something. Any ideas?

 

It does have electric choke. The list number, is that onth edriver's side of the carb or on the passenger side but closer to the body. Never heard of this but will explore...

 

We could use some close up pictures.....

 

Electric choke is coming back on,ck adjustment

 

Make sure you are getting the correct voltage to the choke wire.

SPark

 

The list number is stamped on the air horn (the top housing that holds the choke plate). Hiding under the air cleaner

 

Also, check if your return spring is closing the throttle all the way.

 

Thanks for all the replies. I'll be getting back to this in a couple of days. My dad told me when I was a wee lad that carburetor was Latin for "keep your damn hands off!".

 

The problem can also be caused by the fast idle cam sticking, and not allowing the rpm to decrease as the engine warms up. If this is the problem, it can sometimes be solved by spraying it with WD40, or even carb or engine cleaner, and manipulating the fast idle cam until it frees up.
If the carb is a home rebuild, the problem can also be from one of the external pieces being installed improperly.
Bob

 

Brand new Holley out of the box.

 

Ideas? Here's a couple. Leave the air cleaner off. After it sets for a few, open the hood, blip the linkage off idle and see if the choke plate moves towards closed position. If it does, look at the idle screw and see if it's off the stop. If it is, you already answered your own questions . Loosen the choke stove and back it off some.

 

Could something like a wire, vacuum hose, or even a binding return spring, be preventing the throttle from closing all the way? While looking from the top, carefully check the function of the throttle and secondary plates, to make certain they are operating correctly.
It doesn't sound like a vacuum leak, but check all the hoses.
I hate intermittent problems.
Bob