3.0 I/O mercruiser will start but has trouble idling especially when putting in gear

[Trent_Edwards30]

I have a 1990 Maxum, and it has a 3.0 I/O mercruiser on it. The engine will start just fine when I choke it, but when I bring the throttle back to put it in nuetral it shuts off like it just isn't idling high enough. I can put it in gear if I try to do it fast after choking the engine and the boat runs just fine after it has increased RPM's. This problem seems to get worse the longer I keep the boat out. Also most of the time if I have run for a bit and I come down to idle it seems like it runs wells just a little low.

I keep wondering if simply adjusting the throttle cable will allow the engine to idle just a bit higher so that it can run in neutral.

 

[Bondo]

Re: 3.0 I/O mercruiser will start but has trouble idling especially when putting in g

I have a 1990 Maxum, and it has a 3.0 I/O mercruiser on it. The engine will start just fine when I choke it, but when I bring the throttle back to put it in nuetral it shuts off like it just isn't idling high enough. I can put it in gear if I try to do it fast after choking the engine and the boat runs just fine after it has increased RPM's. This problem seems to get worse the longer I keep the boat out. Also most of the time if I have run for a bit and I come down to idle it seems like it runs wells just a little low.

I keep wondering if simply adjusting the throttle cable will allow the engine to idle just a bit higher so that it can run in neutral.

Ayuh,.... Welcome Aboard,... Has it had a Tune Up, 'n Service lately,..??

it should idle at 700 rpms or so...

 

[Gaden]

This is the same problem I am having with my 1989 Sea Ray. Today when I took the boat out on the water, I had same problem. After draining all fluids, draining tank, replacing plugs, etc...the but ran well especially since it hadn't been on the water for 8 years. All checked out...good temp, good oil pressure, ran well on top end, but WHEN TRIED to IDLE...it would die...My dad said that 8 years ago the boat would idle rough...SO the mechanic turned up idle speed. Now the boat won't idle at all. When I start it and give it gas, it does fine. The acceleration to top speed is smooth...but if I need to idle or put in reverse it dies. What do you think it might be? I think it might be carb gummed up from sitting. IS it possible to clean carb without rebuild? Any help would be great! I hear a lot of good about Seafoam. Thoughts.

 

[GA_Boater]

This is the same problem I am having with my 1989 Sea Ray. Today when I took the boat out on the water, I had same problem. After draining all fluids, draining tank, replacing plugs, etc...the but ran well especially since it hadn't been on the water for 8 years. All checked out...good temp, good oil pressure, ran well on top end, but WHEN TRIED to IDLE...it would die...My dad said that 8 years ago the boat would idle rough...SO the mechanic turned up idle speed. Now the boat won't idle at all. When I start it and give it gas, it does fine. The acceleration to top speed is smooth...but if I need to idle or put in reverse it dies. What do you think it might be? I think it might be carb gummed up from sitting. IS it possible to clean carb without rebuild? Any help would be great! I hear a lot of good about Seafoam. Thoughts.

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Closed.