When my 67 BB gets good and warm she won't idle at a stop light.

[Douglas L.]

Re: When my 67 BB gets good and warm she won't idle at a stop light.

This is the same scenario a buddy of mine had with a 67 - 435 car. The engine ran great when cold. As soon as it warmed up, it would not idle below 1500 rpm. At a stop light, you would have to keep your foot on the brake and the accelerator at the same time. The process to find the problem took years because it was easier to cover the car and forget about it than drive it. I kept telling him, the problem is in the idle circut of the middle carb. He kept saying the carb is rebuilt so the problem cannot be there. It has to be a vacuum leak somewhere. Or, it's got to be the gas. Or it's must be the distributor. Finally, he agreed to take the middle carb of and take it to a carb shop where the carb shop owner put it on another motor. When the carb shop owner tried to run the motor, it would run, but it would not idle. The problem with the carb turned out to be in the metering block. The metering block, which is a major part of the carb idle system, had the right numbers, but something was definitely not right with it. So, the metering block was replaced and now his car purrs like a kitten at idle. So, it all else fails, try the carb on another motor if you can.

[Timothy B.]

Re: When my 67 BB gets good and warm she won't idle at a stop light.

This is the same scenario a buddy of mine had with a 67 - 435 car. The engine ran great when cold. As soon as it warmed up, it would not idle below 1500 rpm. At a stop light, you would have to keep your foot on the brake and the accelerator at the same time. The process to find the problem took years because it was easier to cover the car and forget about it than drive it. I kept telling him, the problem is in the idle circut of the middle carb. He kept saying the carb is rebuilt so the problem cannot be there. It has to be a vacuum leak somewhere. Or, it's got to be the gas. Or it's must be the distributor. Finally, he agreed to take the middle carb of and take it to a carb shop where the carb shop owner put it on another motor. When the carb shop owner tried to run the motor, it would run, but it would not idle. The problem with the carb turned out to be in the metering block. The metering block, which is a major part of the carb idle system, had the right numbers, but something was definitely not right with it. So, the metering block was replaced and now his car purrs like a kitten at idle. So, it all else fails, try the carb on another motor if you can.

If the engine is in good tune and after doing the idle speed adjustments like Duke outlined, the problem could be what is stated above, also the metering plate in the outer carburetors could be leaking internally causing the rough idle.

Many times the surfaces warp and gaskets dry on these Holleys and present all sorts of issues.

[John M.]

Re: When my 67 BB gets good and warm she won't idle at a stop light.

I guess I've got to start from square one, these old cars take a lot of TLC to keep happy. Thanks for all the help after this weekend I'll post the numbers. Thanks

[John H.]

Re: When my 67 BB gets good and warm she won't idle at a stop light.

When the carb shop owner tried to run the motor, it would run, but it would not idle. The problem with the carb turned out to be in the metering block. The metering block, which is a major part of the carb idle system, had the right numbers, but something was definitely not right with it.

The metering block contains the idle circuit emulsion tubes (and the idle feed restriction), and it doesn't take much crud in the fuel to block or restrict those tiny holes/passages; when that occurs, you won't get any fuel from the idle discharge orifices, but you will from the transfer slot and from the main circuit booster. Result? Won't idle. A good rebuilder will remove the emulsion tubes from the metering block and inspect/clean them, but many don't.