3.0 pistons squeaking... doesn't sound good.

[vroom ZOOM]

Hello

Was working on a friends boat today, after he overheated it. He didn't even know that the outdrive had an impeller. I pulled the drive apart and the impeller was NLA. The pieces dropped down into the intake grate so I got lucky there. Tried to start the thing after putting the new impeller in but it cranks kinda slow IMO and there is a squeaking noise coming from the exhaust. Friend remains optimistic that if we just start it and let it run it will be alright, that the rings are just slightly scuffed, but I am pretty sure the pistons and cylinder walls a cooked. Cylinders 2 and 3 are down on compression. Very low compression. I didn't have a gauge but it wouldn't even blow my finger out the plug hole.

So now for the question: is it worth rebuilding the motor, or should I just junk it and find another motor on kijiji? Or will it be ok if we let it run a little? The motor is a 1989 3.0 (older 3.0 style)

 

[Bondo]

Ayuh,.... Time for another motor,....
Rebuilt or used is yer bud's choice,....

 

[Eric 3.7LX Alpha 1]

You should have replaced the entire water pump kit in the drive including the base since it overheated. Those other parts can get damaged also from the lack of water, also should have looked at the water pocket cover while the drive was in two pieces. It's plastic and in the engine's exhaust in the drive and can melt without water. If it get's damaged it won't let the drive pump water correctly.

 

[Grub54891]

you need to find a good used motor, and swap it out. Or rebuild what you have, keep in mind that rebuilding may not work. if it got that hot it may have cracked the block or head, even the manifold could be comprimsed.

 

[Scott06]

The motor is smoked... Things dont like getting that hot. It isnt going to hurt to try and start at this point, because he is screwed already....

If 2&3 have low comrpession head gasket is probably messed up. Id make sure no water is in cyclinder before trying to start.

 

[vroom ZOOM]

Tried to start it, but it just cranks and backfires through the carb. pulled the head and it seems like the head gasket is blown between 2 and 3. The cylinders look very good, no scratching. can anyone please tell me the fel pro part number for a 1989 mercruiser 3.0 head gasket. I wonder if the leak between cyl's would have caused the backfire?

 

[Alumarine]

Tried to start it, but it just cranks and backfires through the carb. pulled the head and it seems like the head gasket is blown between 2 and 3. The cylinders look very good, no scratching. can anyone please tell me the fel pro part number for a 1989 mercruiser 3.0 head gasket. I wonder if the leak between cyl's would have caused the backfire?

Head gasket should be 17000
Head gasket with valve cover and pushrod cover should be 17200

 

[Grub54891]

Stuff the head gasket on there, see what it does. Yeah blown gasket will backfire. Hope it works out.......

 

[vroom ZOOM]

Yay! Threw the new gasket in, compression is back, and the engine sounds good!