1993 50/35 jet stopped at high rpms...

[Loon]

1993 E50JETB

50hp powerhead.

Was running at 5000 rpm and it just quit. Abruptly. Kind of like running out of gas, but in 1 second.

Tried starting it and the flywheel spins around about 320 degrees and hits something hard. I spin it around counter clockwise and it stops after 320 degrees that way.

First thought was broken connecting rod, but pulled plugs and stuck a rod in the cylinders and rotated the flywheel and both pistons went up and down with the almost full turn of the flywheel.

New water pump was working fine and I know I mixed the oil correctly. Plus, the flywheel wouldn't move at all if I truly seized it, right?

I'm busy tonight, but I'll drop the jet tomorrow to isolate the problem. If the flywheel turns after dropping the jet, I know it's the bearing in the jet.

Any thoughts or ideas on other troubleshooting techniques would be appreciated.

[broken_line]

dont sound good! if you ceased it you wouldnt be able to turn it at all. the plugs would be white, connecting rod could be out the side of the motor, it would just go burrr then quit nothing would move.. dont try and move the fly wheel in the direction the motor doesnt turn, you could break the fins off of the water pump.. possibly sucked a rock up then bent the drive shaft.. does it make a grinding noise when you turn the fly wheel? if so its the bearings somewhere..

[hydro]

Look up under the flywheel around the stator. Something could have gone away there.

[Loon]

Thanks, guys...

Jet pump is off and nothing changed. The noise from the posi-stop in the flywheel seems to be coming from just under the flywheel.

I feel like the crankshaft/rods/pistons are not the problem.

The contact sounds and feels like it's happening under the flywheel.

Where do I get a flywheel puller? Auto parts store?

[broken_line]

yea and some hardware stores have them.. you might also whant to fly wheel up at the shaft so it will come off easier.. i bet one of the coils if it has that came loose and is stuck on the magnet, or something similar. good luck!

[hydro]

You don't need a flywheel puller. Get a helper, back the nut off two or three turns or until no threads are showing above the nut (about 1/8") and have the helper lift straight up on the flywheel. Take a 2 lb hammer (heavy is important) and smack the nut lightly but firmly. you want to shock it so the taper releases but not so hard that you break things. The flywheel will pop loose, the nut protects the threads and no special tools are required.

If by some chance this does not work, then go and find a puller to apply the pressure. You still need to pop the puller with the hammer once you have put the pressure to it.

I'll bet that a magnet came loose and has lodged in the stator or coil and the other magnet is catching on it. Been there myself.

[Loon]

Got a flywheel puller and got it off...looks perfect...all magnets intact.

Stator looks fine, too.

Problem remains.

Looks like the powerhead is coming out.

[boatfixer]

Pull the cylinder head for S's & G's. Wouldnt suprise me if you found something in one of the cylinders preventing the piston from reaching top dead center. In any case I'd say it needs to be torn down.

[Loon]

That's what I did and that's exactly what I saw.

Lower cylinder had a 1" long piece of what I assume was a piston ring stopping it from reaching top dead center.

I'll start a new thread for the teardown.

Thanks for all the help so far...Lord knows I'll need more.

Looks like it's back to the 14' and the 9.8 Merc!

[boatfixer]

I kinda thought you'd find that. Keep us updated.