Froze up 25 hp 5842749 serial no.

[Roberthill]

Got this running. Ran it several times in a barrel. 120 psi compression both cylinders. Plenty of oil mixed in with the gas . Tried starting(has electric start) , motor is froze , grabbed flywheel with both hands , won’t budge. Don’t have a clue what happened. Any suggestions? All help appreciated.

 

[Roberthill]

Got this running. Ran it several times in a barrel. 120 psi compression both cylinders. Plenty of oil mixed in with the gas . Tried starting(has electric start) , motor is froze , grabbed flywheel with both hands , won’t budge. Don’t have a clue what happened. Any suggestions? All help appreciated.

Removed lower unit also removed flywheel, motor won’t turn . I suspect ring or rings broke and jammed in exhaust or intake port . What “cover” should I remove ?

 

[racerone]

Remove covers on side of block ( sealed with o-rings ) so no cost.----Likely rusted bearings or dirt inside of engine.

 

[jimmbo]

Did it suddenly quit, or did it slow down and then quit? Or did you shut it down, then tried a day or two later and it was seized? How high were you revving it in the Barrel?

 

[Roberthill]

Remove covers on side of block ( sealed with o-rings ) so no cost.----Likely rusted bearings or dirt inside of engine.

Will do , soon as can. Thanks

 

[Roberthill]

Did it suddenly quit, or did it slow down and then quit? Or did you shut it down, then tried a day or two later and it was seized? How high were you revving it in the Barrel?

Have been running in a barrel every couple of weeks , not real high rpm , tried to start after being shut down a couple weeks and it was froze up.

 

[jimmbo]

"not real high rpm"...
Not 'real high' might be seen different to you than to me. These motors really shouldn't be run above 2000, perhaps even lower, when under no Load.
First step is remove the Spark Plugs and see if water drains out of either Cylinder. If it does, spray copious amounts of WD 40 in to the plug holes and slowly try rotating the Crankshaft. If no tight spots are apparent, then replace the plugs and try running. If binding is occurring, then a Teardown is in the cards, however water in the Cylinder indicates a blown Head Gasket, or a Gasket in the Exhaust Cover, so a Reduced Teardown and inspection is still needed

 

[jimmbo]

duplicate post

 

[racerone]

I do not believe there is a head gasket on this motor.---Just a water jacket cover.----If there is / was water inside this engine all this time it will need a teardown.----You may not like what you find.

 

[jimmbo]

You are likely correct, I was thinking of the OMC 25hp for some reason.

 

[Faztbullet]

Starter bendix not hung up in flywheel?

 

[Roberthill]

Took off side covers , couldn’t see any problem. My son got this motor,don’t have any history information on it . Had 120 psi compression, so I got it running for him . Replaced flywheel , water pump and all the ignition parts . This is what I noticed today , both pistons are about 3” below spark plugs, they are the same distance, I think the crank shaft is busted . My son was running it in a barrel and it made some clanging noise and died. He didn’t try starting it until about three weeks later , and that’s when he discovered it was froze. I believe motor is a lost cause . COMMENTS PLEASE

 

[racerone]

Taking it apart would be good " learning "------Better than reading a book about it.-----Post what you find.-----Perhaps find a donor motor with good parts.

 

[merc850]

Replacing the flywheel is unusual has the new one caused a jamming problem?

 

[Roberthill]

Replacing the flywheel is unusual has the new one caused a jamming problem?

Replaced due to broken magnets. Don’t understand “jamming”.

 

[jimmbo]

Replaced due to broken magnets. Don’t understand “jamming”.

Jamming as in Jammed Up or as you called it, Froze

 

[Roberthill]

Finally got time to tear it down . Bottom main bearing was rusted causing crank to be unable to turn . Going to sell for parts , if possible.

 

[Roberthill]

Remove covers on side of block ( sealed with o-rings ) so no cost.----Likely rusted bearings or dirt inside of engine.

Rusted bottom main bearing , thanks Racerone.