97 Mercruiser 5.7 Great..... then oh boy:(

[skongolf]

Today I had my new(New to me) 97 maxum SFL with a 5.7 mercruiser out on the lake and it started off great. Started right up. The boat hadn't been run really in 9 months and just had some service work and seals replaced. Well I trottled up and took off and everything was great for about an hour. Soon if I turned the motor off, it would start, idle rough and then die when I tried to put it in idle. Did this a few times then ran ok for about 20 min. When we decided to cruise close to shore fairly slowly, it was running rough and kept dying, but would start back up. We saw some stranded boaters and tried to help, but every time i started the boat, it died when I tried to put it in gear It got harder to start and finally it seemed flooded. Well after 10 min it started back up and I headed for the dock. Of course when i got in the no wake zone it idled rough and died and I couldnt get it started at all. It sould start fine in throttle only mode, but when I tried to start it normally it would idle rough then die when I put it in gear. So after a half hour wait it started right up and i got it to the dock. Another 20 min waiting for our turn at the ramp and it started right up again and we were able to trailer it.
Anyway, the temp ran between 150-170 and there was very little water in the engine compartment. Just curious what you guys think it might be before i take it to the mechanic tomorrow. I did do a search, but some stuff seemed different than my situation. I called my mechanic from the lake and he though it was the neutral interupt switch possibly.
Any thoughts?
Thanks

 

[jtybt]

Re: 97 Mercruiser 5.7 Great..... then oh boy

Dying trying to take out of gear is often sticking lower shift cable. But sounds like you have flooding problem. First and easiest is check that the choke plate opens all the way.

Diagnosing a problem is mostly a process of elimination...but we have to know all the facts and info on your particular boat. A lot of times recent maintenance history is helpful.

 

[John_S]

Re: 97 Mercruiser 5.7 Great..... then oh boy

Is this the 2brl Mercarb 5.7? If so, remove flame arrester and using a flashlight look down the barrels. If you see gas dribbling while idling, the float needle is sticking. This happened to my Mercarb on 5.7L. Got so bad you could see gas sitting ontop of the butterflies. A new float needle and seat are part of a carb rebuild kit.

I have since gone to 4brl carb, but after a year started to develop similiar problem. Turned out, the mechanical fuel pump was putting out too much pressure (9+lbs). You may want to have your mechanic check that as well.

 

[ENSIGN]

Re: 97 Mercruiser 5.7 Great..... then oh boy

CHECK YOUR FUEL,take a sample from the tank and empty the fuel filter in a glass jar and check for water!