Idle mixture screw question

[Buzzmobile]

mine are very loose and they back out on their own, I am constantly resetting them. My carbs look pretty old, but not sure if there is an easy fix for this. Is it the threads in the base of the carb? the screws themselves? I have a 2x4 set up and not the best carb mechanic on the planet...

thanks for the help

Buzz

[Roscoe]

You might need new springs to keep tension on them.

Roscoe

[wizard]

Are there springs around the screws? The springs put tension on the screws to keep them in place. If they're there, try stretching them a bit so they'll exert more tension. Do it a little a time. You don't want to over stretch them. Or better yet replace 'em. I believe the screws and springs come as a set.

Another trick is to take a pair of pliers and ever so gently distort the threads on the screws. Be VERY careful not to go too far and don't mar the end of the screw where the air/gas ratio (for idle) gets regulated. This will cause the screw to bind slightly, hopefully locking it in place.

If it's the screw or the carb housing is a hard call but would guess it's a combination of both. I believe the seat or jet (what ever is the correct terminology here) can be replaced as well as the screw, but I'm not sure about the threaded area on the housing although I would be surprised it it could. Good luck.

Again, your best option is to replace both the screws and springs.

[Rick Parker]

Holleys??
Replace the Cork (Holley OEM) or very small rubber "O" rings (Barry Grant/Demon) (interchangeable with each other too) that fit in the counter bored holes that the idle mixture screws thread into. These provide a seal to prevent air leaks and provide and elastic feature (like a nylock nut) to prevent the screws from moving. Or (Edelbrock/AFB type) use the very thin Locktite (green) that is intended to be applied after the screws are "set" It wicks into the threads. Easy to "Undo " as needed.
Any good speed shop or carburetor vendor should be able to supply them separately OR they are in a Carb rebuild kit too.

[cosbytnkid]

Buzzmobile I have to agree with what Rick says here. It should only be a minor fix to cure the back out problem.

[Buzzmobile]

yes, they are holleys. Not even sure they have springs....don't think so. Are they supposed to? Thanks for all the help...

Buzz

[undy]

Originally Posted by Buzzmobile

yes, they are holleys. Not even sure they have springs....don't think so. Are they supposed to? Thanks for all the help...

Buzz

...as Rick said. Replace the cork o-rings and you'll be fine.