Engine locking Up 3.0 OMC

[carhopper]

Hello, I have a 1993 OMC Cobra in my 17.5' Carvelle bowrider. I took it out for the first time this summer and it ran great for about the first 15 minutes then locked up suddenly. When it locked I heard an abrupt metallic sound in the front of the engine. The engine would not turn over except very slowly.

I let it cool for about 30 minutes and it started up again, then shut off after several minutes with the same slow turn over.

Temp is 160-170, oil pressure is 40psi at idle.

I did have one problem since last summer. I didn't get all of the water out of the block and I had a crack in the block under the intake. I removed the intake, wire brushed to bare metal, and put JB Weld on the crack. It no longer leaks.

When I run the engine with mouse ears, it does eject water from the rear. I thought maybe I obstructed the water path with the JB Weld.

 

[Bondo]

Re: Engine locking Up 3.0 OMC

I took it out for the first time this summer and it ran great for about the first 15 minutes then locked up suddenly. When it locked I heard an abrupt metallic sound in the front of the engine. The engine would not turn over except very slowly.

Ayuh,... That's not much to go on,...

Motors usually Don't mechanically Lock up,+ then let go...
Did you pull the plugs,+ Look for Water,..??

 

[carhopper]

Re: Engine locking Up 3.0 OMC

I really didn't do anything yet, it was late yesterday when it happened. There isn't water in the oil, I checked that. I'll check the plugs next.

Do you think it could be a leak since I pulled the intake?

 

[carhopper]

Re: Engine locking Up 3.0 OMC

I took the boat to a marine mechanic and the upper gear box was low on oil and pretty eaten up. The sound was being transferred to the front of the engine. He removed the box and started the engine briefly and no noise.

Now I have a question for the experts. There appears to be a difference between 86-89 3.0 OMC and 90-93 as they are two different part numbers. I found a gearbox on ebay for a 2.3 1989 that he says will work on a 3.0. My mechanic says that it will work on my 1993 as well. The only difference I see is the gear ratio. The 1989 is a 21T/18T and my 93 is a 21T/21T. This means the boat will go faster, but less torque out of the hole right. How profoundly will this affect things.