Engine Idle/Carb adjusting

[Don St Peter]

I finally bit the bullet & purchased a completely rebuilt ( to original specs ) carb. for my 40 Ply. After carb. installation and adjusting the throttle screw to what seems to be 400 to 500 engine RPMs, then the idle screw adjustment to smooth, and then the throttle screw again with engine hot as instructed, the engine will not return to proper low idle unless I tap the gas pedal slightly. Once I do that it idles back down.

Is this normal or am I missing something here.

Thanks in Advance

Don

[randroid]

Don,

There are two major factors that would cause that condition and they're both pretty simple to fix.

#1. Friction.

#2. Friction

Fixing #1: The quick and dirty method would be to install a stronger return spring, but since your carb was recently rebuilt it may already have one. I'd doubt that it does, but if you take care of the second fix it probably won't matter.

Fixing #2: I have a friend who is a DEA Agent. He carries a .357 and personally polished the double-action mechanism to work not with several pounds of pull but one measured in ounces. Our throttle mechanisms are Goldberg-esque, which is part of their charm, and there are several places which less that an hour of easy labor would fix, and once you do them you'll notice a great difference. like ounces versus pounds. Don't worry about it becoming overly sensitive because you adjust that with the main return spring and your right foot; what you'll benefit from is a lessened drag within the system, ergo less sticking and the problem is stuff sticking from friction. I polished all swivel joints with 600# w\d and then greased them with a lithium based grease (which is over-kill but I have some around and I think it looks neat) and hit the ball joints with jeweler's rouge inside and out. By the time you open your second beer, find an old points file and polish anything that's left. If you do a half-assed job you'll be happier, and may be inspired to do it even better.

It worked for me.

-Randy St John

[greg g]

You also might want to check the linkage from the choke to the high idle cam and assure that it is adjusted properly and not sticking.

[claybill]

spray the inside with carb and choke cleaner..and INSTALL A STRONGER RETURN SPRING..and check the nuts on the ends of the throttle actuating rods for tightness. a little slop in loose nuts and bolts will give just enough to inhibit proper return.

bill