Is there a difference in teh AUtomatic tranny vs Manual tranny carbs...i bought non feedback carb to dumb down my truck and the idle is too high, now ive unscrewed the idle speed screw and disconnected the throttle cable and pushed the throttle plate closed and it still idles at around 800 rpm and I can't bring it down lower...somtimes it' idles at around 1000.

Any suggestions to what it could be?

Thanks,
John

 

Check for a vacuum leak. All it takes is just a little extra air to bump up the idle - this would also make the fuel/air a little leaner and the engine hotter too. But I don't know if there would be any differences in carbs due to auto or manual trannys that limit the idle settings. Usually a carb can completely choke off an engine and stall it with the throttle plate completely closed.

 

thanks, yeah I have been thinking about tha the past couple of days...trying to think if where I Might have a vacuum leak.

 

could also be that its simply running too lean.

I'm no carb man, but i believe a lean condition can cause i high idle.