Inliners International Forums General Discussion Engines Idle Speed - Dual Rochester DC Carbs

I think the plug gap is a bit wide for a stock distributor-I believe it should be more like .035". The .045" gap is more for HEI fired stuff. However I dont think that would cause an idling problem.

If each model B carb ran fine by itself on a car then I would think that you should try to change out the power piston springs like they say to do in the tech articles on this site--this will make for a crisper throttle and keep it off the power stage (rich & bad milage) because its not uncommon to have less manifold vacuum with multiple carbs (more places to leak vacuum and more potential worn throttle shaft leaks) and with less vacuum the power stage could be coming in too soon and even possible to be there at idle. I've had that happen to me on v8s using two "perfectly" tuned stock 4 bbls--at idle these "perfect" carbs would run so rich your eyes would tearup from the black exhaust. It could be the motor dying maybe from an overich mixture when warmed up. When cold the extra richness wont affect it too badly, but as it warms it dont need the extra richness. good luck! I wouldn't worry 'bout the grade of gasoline, nor the fuel pressure from a stock pump.

The manometer is a step up from a unisyn-so no problem.

See if its a mechanical linkage issue, or a mixture issue or maybe an ignition problem. You could check for plug spark by looking at a timing light (no need to be a machoman an' grabbin' a plugwire-besides it would play hell with your pacemaker and make your socks yellow!!)