72 dart 318 problem please help

[moparjon]

ok, 1972 dart 318 2-barrel stock . when driving down the road, and let off the gas , the engine does NOT slow down to idle , then after about 8 seconds it starts to lower its rpms slowly back to idle . it is NOT the linkage , the linkage is NOT binding up anywhere . when in park and i manually pull the accelerator . it behaves the same way . kinda like a run-on . this just started doing this yesterday. all i can think of so far is carbon build-up in the engine , i tried carb cleaner with NO results . anybody have any ideas ? please help -thanks

 

[grumpuscreature]

Sounds to me like your dashpot is sticking. It looks like a small vacuum canister that is screwed to the carb and has a plunger that contacts the throttle linkage. It's purpose is to ease the throttle back to idle and theoretically reduce unburned hydrocarbons. I would remove it and see if that fixes the problem (it's held on with a couple of screws). Then you have to decide if you want to replace it or leave it off. Hope this helps.

 

[moparjon]

thanks , it seams to have been a vacuum leak from the hose that goes from the bottom back of carb , to the charcoal canister .