Carb Cough

[cly_mitchell]

I have finished my car re-build. The advise I was given was great and helpful. But while tuning the carbs, the have aquired a cough at idle. I have tried to richen the mixture, but no joy. I seems to decrease if I lean the mixture. The carbs a set at less that a full turn out right now. I have checked the O rings and they are ok. I have done the old propane trick and no leaks have been found. I have balanced the carbs, and the intake flow is the same.

I changed the ignition to the pertronix electronic type. My coil reads 1.6 ohms, so I should be ok there. The timing it set correct.

I may have had this problem before the rebuild as the car ran rough at low speed. I never heard the cough due to turbo plumbing.

I have tuned carbs before but this has me scratching my head. I done everything I know related to a cough short of dropping my drawers and turning my head.

Anybody have an idea?

[semi42]

similar thing happened with my 79 s2 non turbo. after removing the carbs and manifold for polishing.

when refitted, cyl 4 would cough and spit back, i thought it was the carb itself so i swapped the carbs around and still the same problem. changed o rings, inlet manifold gasket, dizzy cap, plugs and wires and still they coughed.

balanced the carbs with a manometer and they seem fine now.(fingers crossed)

[cly_mitchell]

I changed my tactics. I was using a flow meter that measured the air entering the the carb to start. But when I checked the vacuum they were different. So, I have re-balanced the carbs with vacuum gauges and they have cleared up. I will test drive and hopefully all will be well.

Thanks again

Cheers

Clay

[Esprit Aviation]

Carb problems aside, check to make sure that your coil resistance is correct. I thought it was supposed to be 3.0 ohms. Otherwise the switching transitor may be handling twice as much current than it was designed for, and it will burn out.

Lee

[cly_mitchell]

Carb problems aside, check to make sure that your coil resistance is correct. I thought it was supposed to be 3.0 ohms. Otherwise the switching transitor may be handling twice as much current than it was designed for, and it will burn out.

Lee

Hello there Lee,

I switched the ignition to the pertronix set up. It says the coils should be .6 ohms or more. I am going to put the pertronix coil on just to make the set. I could not bring myself to put a DIS like yours on the car. In the last two years the car has had 20k invested and another k for ignition just seemed to much. I am past the point of diminishing return already.

I was getting a new motor for my boat. So, I called a guy who sold new Mercruisers about his motor. He said it would be 9k for a long block. Once I caught my breath, I asked if he was sh*itting me. He said " Mr. it is my experience if it floats, flys,or f*cks its expensive". I am trying to work exotic cars into that saying.