Could it be siezed

[joeyd50]

My son just picked up a 1995 boat with a 1995 Mercury 50hp, the guy he bought the boat from said, last he used it was August, motor won't turn over and I couldn't turn it by hand, I believe the guy ad his Dad who said it ran great. Do you think it could sieze up that quick? Anything I can do to try and free this thing up.
Thanks
Joe

 

[alldodge]

Don't see it locking up that fast. Pull the plugs

 

[jimmbo]

Drop the lower unit. If the engine then turns freely the problem is the gear case. If still seized, then spray copious amounts of Combustion Chamber Cleaner/SeaFoam/or your favourite penetrating oil into the spark plug holes. After letting it sit many hours, try rocking the flywheel back and forth. If still stuck, it is time to open er up

 

[Chris1956]

When rebuilding my boat, I removed the motor and laid my inline six on her side on the floor. This was in the spring, so the motor was well drained. A drop of water somehow found a ring face and rusted it to the cylinder wall. just a spec of rust.

I whacked the top of the piston with a brass drift to free her up.

 

[SeaDooSam]

Drop the lower unit. If the engine then turns freely the problem is the gear case. If still seized, then spray copious amounts of Combustion Chamber Cleaner/SeaFoam/or your favourite penetrating oil into the spark plug holes. After letting it sit many hours, try rocking the flywheel back and forth. If still stuck, it is time to open er up

I have had good luck dumping a bunch of Marvel Mystery oil down there

 

[Faztbullet]

Is this a 3 or 4 cylinder????

 

[DeepCMark58A]

PB Blaster.

 

[racerone]

Manual start ?-----Is it in nuetral ?-----Post pictures or serial #

 

[Silvertip]

Whacking the piston with anything is a great way to fracture the piston crown. Using a long breaker bar is also a good way to break rings and ring lands. Gentleness is the way to loosen the engine. I suspect the engine was siezed the day you bought it. Runs great means nothing unless YOU make that determination.

 

[DeepCMark58A]

Very true Silvertip, when it comes to buying any used boat motor, trust but verify.

 

[joeyd50]

Is this a 3 or 4 cylinder????

3Cyl.

 

[joeyd50]

haven't looked at it yet, my son going to drop it off so I can play with it, I'll get back to you guys soon as I get my hands on it.
Thanks everone
Joe

 

[Faztbullet]

If its the 3 cyl looper these are bad about sleeves slipping and piston rings fall behind the sleeve only allowing about inch of movement of flywheel.....

 

[joeyd50]

My son put a little oil in all cylinders and it crank, thanks for all the suggestions.

 

[DeepCMark58A]

Thank you for the update, all too often a poster never comes back to let us all know how the situation was resolved. I know I am always curious if things worked out.

 

[joeyd50]

No problem, I always see post , not just here, that have a problem I'm interested in and never see what the outcome was

 

[60sboater]

Me too...does it run or just crank?