wcfb choke stuck again!

[Don Izzo]

Gentlemen, I have been trying to resolve this choke problem for some time. Again the choke is stuck in the open position after normal operation and cool down cycle. Upon disconnecting of the choke linkage rod , I find that the lever coming out of the back of the choke housing is stuck. I again disassembled the choke assembly and find nothing other than the vacume piston is stiff in the bore. No debree, carbon buildup, no obvious reason for it! My questions are this: The piston is held to the link by a pin. The pin floats in the piston and can walk left or right and even protrude out of the piston when it is in my hand. Should this piston pin be staked so it cant walk out and rub the walls of the bore? could this be the problem or is either the piston swelling or the bore shrinking when hot. The piston doesn't un-stick when it cools down. I buffed the piston with some fine wet/dry paper and reassembled and it works fine on the bench. But did this last time along with a fine honing of the bore and it stuck again! Do these piston commonly fail and need to be replaced. Hate to scrap this assembly they are too hard to find!

Don

[James F.]

Re: wcfb choke stuck again!- Don

Don, Sounds like you are doing all the correct work on the pison and choke bore. The piston is NOT staked to the lever. As you found it is the way it should be.Double check t hat the lttle lever is not cocking the piston in somway at the bottom of the choke bore. You might "mike" the inside of the bore with a micrometer and the the outside of the piston to know what dimensions you are dealing with. Since the interference is at the bottom of the bore I think I'd concentrate there with first the bottom of the bore by polishing it a shade larger.
Sounds like you you're dealing with "just one of those things," a fussy choke bore and vacuum piston assembly. Maybe swap the parts out if you can come across an old junk WCFB. Generally I find that if you n"noodle" with something long enough, you usully get it to work. Regards, Jim

[Don Izzo]

Thanks Jim! *NM*

[James F.]

Further thought.

Don, Thinking more abut this during lunch, double check that the choke rod passing through the main body and choke plate are "free" open position. I've seen chroke rods bent a little which cuses them to "bind". Regards, JIm