1989 yamaha 150 hp cranking problems?

[erock7678]

I'm new to this forum and I just trade my little Jon boat for a 20' Proline. I started the yami and a lot of white smoke came out and then cleared up. water sight hole was working fine and the motor sounded great just a little high idle but ran great. A couple days later I went to start it again and the motor wouldn't turn I thought it might be the batteries so I charged them up (I just bought them this year). Tried it again and nothing. I took the plugs and tried to turn over and still nothing. Then i put a socket on the flywheel and turned it over but even with the plugs out it still turned pretty stiff and there is a squealing noise. Please if anyone has any suggestions let me know what it might be. I was wondering if there was some kind of pressure release or something that I'm missing? My engine model is 150etxf year is 1989.

[rodbolt17]

one of three things.
the drive shaft bushing locked up,the lower unit failed or the powerhead failed.
time to drop the lower and see what failed.

[CaptRandy]

I also vote for the drive shaft bushing frozen. Located in mid unit, you can see it with a flashlight when you drop lower unit. It sometimes ****s at an angle and traps the shaft stopping it from turning.

[erock7678]

Is that a major job or can a person with good mechanical skills handle it?

[robert graham]

The drive shaft bushing is not a big complex deal, just look up in there with a flashlight and try to determine condition. I beliece it's held in with a circlip. It's just a black rubber bushing that can require some lubrication to prevent sqealing noises. Are your battery cables and connections clean and tight?

[erock7678]

Yes all battery connections are good.

[robert graham]

Seems odd it was running fine when you put it up, then upon restart it was tight, stuck, whatever. I'd remove each spark plug and shine a flashlight in each hole to look for water, carbon, condition of cylinders. Maybe a water leak into cylinders set up corrosion on rings and cylinders? Spray WD-40 or similar in each cylinder and try to turn it over? Good Luck!

[robert graham]

Another possible idea might be a nut/bolt/fastener/component shook loose under flywheel and jamming it when turned...could remove flywheel to inspect?