Seized Motor?

[johnscram]

Hi guys! Ive been a member for a few years now and I love the forum. I don't post much but I'm always looking up and searching stuff on here. I was out running my 1985 Bayliner Capri on Sunday with a AQ125A with a 275A outdrive. I was towing 2 people on a tube and 5 people in the boat so it was under a heavy load, the motor was cooling well and everything seemed fine, then all of a sudden I heard a noise that sounded like a can inside of the motor and then immediately it lost all power and died. It went from about 3500 rpm,s to a dead stop in about 4 seconds. I tried restarting it but it only cranked very very slowly and wouldn't restart. So after I paddled us half a mile back to the boat ramp and pulled the boat. Last night I removed the outdrive just to make sure that wasn't the problem. The drive is fine and was full of good new oil. The motor still wouldn't crank very fast, even after I took the plugs out and lubed the cylinders because I also had a theory about the oil pump dying and the motor seizing. So after that I decided to pull the motor figuring it was probbably partly seized. I got the motor out and what do you know, after I separated it from the bell housing it turns very freely. The intermediate bearing is definitely shot in the bell housing. But would that be enough to stop the motor like that? The intermediate shaft still turns, even though the bearings feel rough. I'm just lost here! Thanks for any help. John...

 

[RogersJetboat454]

Re: Seized Motor?

But would that be enough to stop the motor like that? The intermediate shaft still turns, even though the bearings feel rough. I'm just lost here! Thanks for any help. John...

Why not?
Bearings can go from smooth rollers to clutches that grab things and slow them down. This is one of the principles used in some automatic transmissions. If the part spins one way, you get smooth bearing action. If the part spins the other way, the rollers bunch up and grab the part, stopping it from spinning. Obviously your not spinning the shaft in two different directions, but a regular bearing can do this if the cage that separates the balls or rollers is damaged, and allows the rollers/balls to bunch up together.

When you go to replace the bearing, check the housing and intermediate shaft for scoring, since there may be a chance the bearing spun on either of them. And do remember to grease the new bearing periodically through the grease cap on the top of the bell housing.

 

[johnscram]

Re: Seized Motor?

Why not?
Bearings can go from smooth rollers to clutches that grab things and slow them down. This is one of the principles used in some automatic transmissions. If the part spins one way, you get smooth bearing action. If the part spins the other way, the rollers bunch up and grab the part, stopping it from spinning. Obviously your not spinning the shaft in two different directions, but a regular bearing can do this if the cage that separates the balls or rollers is damaged, and allows the rollers/balls to bunch up together.

When you go to replace the bearing, check the housing and intermediate shaft for scoring, since there may be a chance the bearing spun on either of them. And do remember to grease the new bearing periodically through the grease cap on the top of the bell housing.

Thank you sir! I knew that was possible to happen with the bearing. Im going to do more investigating after I get home from work. I'll let you know how it goes.