1977 Mercruiser 140 won't idle

[jackball42]

I have a '77 Starcraft with a Mercruiser 140 that wont idle. Rochester 2bbl. I had the boat out two weeks ago and it worked fine. Just prior to that trip I had rebuild the carb, new points/condensor, plug wires and cap. The boat had been sitting for many years before I got it and the accelerator pump was gone and there was quite a bit of varnish in the car. After rebuilding I ran some Seafoam through the tank to help clean the fuel system as a whole. I had it out today and it wont idle for nothing. The boat runs great with a little throttle and runs great at WOT. Where should I start looking? I read a post about the idle cam flipping over but havent looked at mine yet. The engine shakes a litte at low RPM's, like 900-1000.

 

[Bondo]

Re: 1977 Mercruiser 140 won't idle

I have a '77 Starcraft with a Mercruiser 140 that wont idle. Rochester 2bbl. I had the boat out two weeks ago and it worked fine. Just prior to that trip I had rebuild the carb, new points/condensor, plug wires and cap. The boat had been sitting for many years before I got it and the accelerator pump was gone and there was quite a bit of varnish in the car. After rebuilding I ran some Seafoam through the tank to help clean the fuel system as a whole. I had it out today and it wont idle for nothing. The boat runs great with a little throttle and runs great at WOT. Where should I start looking? I read a post about the idle cam flipping over but havent looked at mine yet. The engine shakes a litte at low RPM's, like 900-1000.

Ayuh,... Sounds like there's still, or more crud in the idle circuit passages,...

ya might try another rebuild....

was it soaked in solvent, 'n blown out with compressed air,..??

 

[jackball42]

Re: 1977 Mercruiser 140 won't idle

I soaked it in carb cleaner and blew out the passages with air. Based on the amount of varnsih in the carb I wouldnt doubt that there is still some crud in there.

 

[jackball42]

Re: 1977 Mercruiser 140 won't idle

I am going to pull the carb off, again, and get a tank of Berryman's chem dip and soak the metal parts from the carb to make sure I get all the crud out of them. I just used Gumout spray befoe.