[Acooljt]

I believe I need to adjust the idle fuel mixture on the car and adjust the choke. Well, you're suppose to adjust the choke when the engine is warm, but when my engine becomes warm, it dies. Now what I've been told is to put the idle mixture screw in all the way and then back it out 1 and a half revolutions to at least get you started. And it does get me started, but as soon as the butterfly gets open and it warms up, it dies. But I tried backing out and putting the mixture screw in and out, and neither way helped, so I think the choke needs adjustment. So you can see I'm in a pickle. Any help?

[Jeff65]

There's four adjustments on most carburetors:

a. Idle mixture
b. Idle speed
c. Fast Idle Speed
e. Choke

When the carbs not in tune, you want to:

a. Set choke to off by unloading the choke linkage (kick down the accelerator linkage max and choke should unload (open fully). This is a check to see the choke linkage works. Kick again and the choke should close to within 1/16" of air horn but not completely close. If hard closed or if too far open, adjust choke to get 1/16" open (or carb rebuild specification clearance).

b. Set idle speed screw up.

c. Set mixture screws to 2 turns open from closed position.

d. No adjustment to fast idle is required.

Start engine. Engine should run at fast idle and as it warms up, should cause choke to open. Since both fast idle and idle speed are turned up, the engine should continue to run on its own. If it doesn't, something is wrong with carb, intake leaks, etc. Once warmed up and choke is fully open, kick accelerator and allow idle speed down to 600 rpm (approximately). Adjust idle speed as required.

Once idle speed is down, adjust mixtures. This depends on carb. Some adjust to lean idle roll off and some adjust to max vaccuum/rpm at idle.

Carbs requiring adjustment at lean idle roll off. Adjust idle mixtures toward closed until engine rpm drops off, back off 1/4 turn. Repeat for other idle screw if applicable. Back off 1/4 turn. Repeat three times to get best adjustment of both idle screws.

Carbs requiring adjustment at max vaccuum, rpm. Need tach (0-1500rpm) or vaccuum guage. Connect tach or vaccuum guage. Adjust idle screw closed until rpm drops off. Back off 1/4 turn. Repeat for second idle mixture screw. Now open one idle mixture screw to just achieve max rpm or max vaccuum...go no further. Repeat for second mixture screw. Stop engine. Carefully count turns to close both mixture screws. Open each to the mid point calculated from the turns required to close each. Example: if one screw setting results in 1 and 1/2 turns to close, and the other requires 1 and 3/4 turn to close, then open both 1 and 5/8 turns (split the difference). Do not readjust once achieving this setting. It is the ideal setting for both screws.

Once idle mixtures are adjusted, start engine and set idle speed. Rig choke linkage for fast idle and set fast idle speed. On some carbs fast idle is not adjustable. On some carbs fast idle can only be adjusted with cold engine.

[Acooljt]

Thanks dude. I know everything is okay with the carb because we had it running and idling fine before. Thanks much though dude, I'll give it a try later and post results.

[Acooljt]

Well, it's come down to it, we gotta rebuild the carb. I knew it was gonna happen, I already have the overhaul kit and everything, I was just hoping the carb would hold up a little longer, until the winter. Ah well, I knew it was coming.