Mercruiser will not idle.

[sacpdg]

Hello, i have a 1976 mercruiser with a 302 ford and 2barrel Rodchester carb. I start the motor and it warms up and will idle for a while. After running great at any speed nit close to idle, i cannot get it to idle anymore. I adjusted the choke and when warm, the choke is almost wide open, and when cold, it is close to closed. I have new spark plugs, cap, rotor,and wires. Thanks for the help.

 

[mpdive]

Re: Mercruiser will not idle.

Can you et to the mixture screws? If so, turn them in fingertight till just seated and then two turns out and see if that helps. If so get a tach or vac gauge to do the final setting. MAKE SURE your idle speed is to specs first. If you cant get it to stay running bump the idle up by about a hundred for an initial mixture adjustment and then reset to factory spec. You may need a carb rebuild but it's worth trying first before chasing your tail on this. Also make sure you are not working against a vacuum leak. It's possible the idle passages could be plugged but again worth a shot. Being a 1976, theres always a chance the carb has never been touched.

 

[sacpdg]

Re: Mercruiser will not idle.

I will adjust the mixture screws. What should i check for the vaccum leak. Just the hoses to the carb? Thanks for the help

 

[shrew]

Re: Mercruiser will not idle.

I suspect a carb issue. Such as partially clogged jets. when you actuate a choke, you're actually closing hte choke. When the choke is off, it is essentially open. When you first start it the automatic choke will close the choke. After running around with the engine will be warm and the choke will open again. It sounds like when the choke is open, you are running in a lean condition where the balance of fuel and air is heavy on the air. This can occur if the jets are partially clogged. You can see this on things like dirtbikes and small outboards with a manual choke were the choking it can resolve the issue. That is really a temporarly issue. I'd look at getting teh carbs cleaned and rebuilt.

 

[mpdive]

Re: Mercruiser will not idle.

I will adjust the mixture screws. What should i check for the vaccum leak. Just the hoses to the carb? Thanks for the help

Anywhere you have a vacuum line especially at the carb base. I have a feeling you are looking at a rebuild. Richen up the mixture and see if it helps.

 

[sacpdg]

Re: Mercruiser will not idle.

Thank you very much guys. I pulled the carb, cleared a clogged jet and runs like a dream!!

 

[NHGuy]

Re: Mercruiser will not idle.

Awesome!