Turning motor by hand-trouble signs?
 

I'll try and make a long story short. Got the boat out of the barn and going to de-winterize and start up. Went to start it up, as motor was turning over, got a bad, really bad backfire! Would not turn back over due to starter problem-think the solenoid went bad because of this! Regardless, starter needs tested.

My motor is a 95 502 MPI. Thought their might be more to this problem, because it seemed more than a typical backfire. Pulled #2 plug and it was completely full of gas! Figured the injector stuck on it and filled up with gas while trying to start. WHAT KIND OF DAMAGE, IF ANY COULD THERE BE? I have pulled rest of plugs and they all look fine without any gas in those cylinders either.

I have turned the motor by hand a few revolutions trying to get rid of the rest of the fluid that was in the cylinder. It seems as if the motor turns fine/easily by hand and I HEAR NO UNUSUAL SOUNDS TURNING BY HAND.

Could this confirm no damage? I plan on doing a leak down test of the cylinder once I get my starter fixed too. Any other advice is helpful. I'm praying no serious damage! Hate to loose the first part of the boating season. PLEASE HELP!

Could have hyd . motor and bent rod ,,worst case !! just fix starter and try again with gas out ,if it was mine thats what I would try and watch the #1 for fuel it most likly o.k. if not P.M. me I;ll help !

Thanks Bobby!
 

Bobby, just got off the phone with someone and he said exactly what you have said-probably hyd. If any other signs show up after going through the necesarry pre-cautionary steps, I will pm you.

Thanks,
Mike.

I'll be very happy to help ,,sorry about your trouble ,,its most likly o.k. !:D

If the motor did'nt fire then you are probably ok. If it turns over slowly again, do not atempt to start it or you will certainly bend a rod. It happened to me last fall and I did bend a rod.

Do you think it is a good idea to pull the valve cover off and check to see if there is a possible bent push rod while rotating the motor by hand?

A bent push rod is very doubtful, your concern would be the connecting rod. After you fix the starter issue, do a quick compression check, that should tell you if everything is ok. If you bent a rod you would have no or almost no compression with that cylinder.

Guess I was a little confused. Thought the above replies were referring to the push rod, not the connecting rod-OUCH!

ido1320, the compression test may not be as accurate as you think. When i bent my rod it was very slight. The motor ran fine and the only thing that gave it away was a slight knock which diminished after running for about 20 sec. when I turned it off to prevent further damaged. What had happened was no. 7 rod bent only slightly enough to cause the pin land on the piston to hit the crank throw. I got lucky and at nearly 500 hours the motor only required replacing tha one rod, rebalance, rings, bearings and gaskets and a valve job, of course. I got lucky!

The motor never did run. Just the nasty backfire. Never had the chance to even turn it back over because of the starter issue. Maybe a blessing in disguise. I probably would have tried cranking again if I could. Taking starter to get tested/fixed today. Hopefully have it back for the weekend for the next go around.

Man, I am hoping everthing comes out ok with this.:confused: :(

Before putting it way last night, I let the cylinder's air out and sprayed a little silicone lubricant in the cylinder that had all the gas in it, then turn the motor a few revolutions to lightly coat the cyliner wall.