Mercury 25hp (5842749 serial #) Locked up.

[Roberthill]

Just got this motor running , 120 psi compression both cylinders, plenty of oil mixed with gasoline, ran it several times in a barrel , shifted fwd and rev , then tried starting ,motor was locked , wouldn’t budge. Does have electric start , took off pull rope starter and tried turning with both hands on flywheel, would not budge. Does anyone know why this happened? Any help would be appreciated.

 

[flyingscott]

Pull the lower unit off and see if it turns then.

 

[Roberthill]

Pull the lower unit off and see if it turns then.

Thanks, will try that .

 

[QBhoy]

Pull the plugs out it. Try it. Or is the starter stuck on the flywheel

 

[Roberthill]

Pull the plugs out it. Try it. Or is the starter stuck on the flywheel

Pulled plugs , no starter is not stuck on flywheel, also removed rope starter .

 

[QBhoy]

Pulled plugs , no starter is not stuck on flywheel, also removed rope starter .

You had the gearbox off it before it started doing this ? So it didn’t turn over even even with plugs out