How to Set Fast Idle on 2818 Carburetor?

[Michael H.]

Can someone please provide detailed instructions (maybe even with photos!) on how to set the fast idle on a 2818 carburetor for an L76 327 C.I. engine in an early 1965 Corvette? I had the carburetor rebuilt by a reputable carburetor restorer, but the fast idle isn't set properly. My NCRS buddies and I are not familiar with the set-up on the this particular carburetor, and we're having problems trying to adjust the fast idle ourselves. (Please excuse our ignorance.) Thanks.

[Michael J.]

Re: How to Set Fast Idle on 2818 Carburetor?

IIRC, that is the same as my '64 L76, and it is good to have three hands to do it. The first thing to do is disconnect the spring on the throttle rod on the driver's side of the carb. Then with your hand under the passenger side of the carb near the choke assembly, rotate the throttle lever to full throttle and you should feel a small (1/4" nut/screw) screw rotate behind the choke cam. That is the fast idle adjustment screw. It is upside down, so to step the fast idle up on the cam, turn it towards the fan, front of the engine, maybe 180 to 270 degrees. Then reconnect the spring on the throttle lever and, making sure the engine is dead cold and the choke plate closes all the way, start it and see what RPM you have. If too much RPM, back the screw out a bit (toward back of the engine), if too little RPM tighten it more (towards the front of the engine). I usually set mine so it builds to about 2200-2300 RPM for spec fast idle, wait a few minutes after you start to see where the fast idle builds to on the tach. In adjusting it, make sure you shut it down quickly and let it cool a bit between, to make sure it is cold enough to set on the cam as cold start position. Hope this helps, good luck.

Here is a picture of what the adjustment screw looks like if you had the carb upside down. BTW, it should not hang on the choke lever as shown in the picture, that one is messed up.

[Timothy B.]

Re: How to Set Fast Idle on 2818 Carburetor?

Can someone please provide detailed instructions (maybe even with photos!) on how to set the fast idle on a 2818 carburetor for an L76 327 C.I. engine in an early 1965 Corvette? I had the carburetor rebuilt by a reputable carburetor restorer, but the fast idle isn't set properly. My NCRS buddies and I are not familiar with the set-up on the this particular carburetor, and we're having problems trying to adjust the fast idle ourselves. (Please excuse our ignorance.) Thanks.

Michael,

There are several adjustments for the hot air choke and fast idle on that carburetor. It's better to find a service manual for your car so you can go step by step to make sure the choke piston adjustment is correct first. The correct way to set the fast idle speed if that's all you want to do is done with the engine hot and choke full open. You set the adjustment screw on the highest step cam and restart the engine then adjust the screw to the RPM spec in the manual. It's something like 2000rpm hot engine so when cold it will be lower.