engine, lower unit or starter?

[redlinj]

Finally got my mercruier 485 3.7 in the lake. It's an '82 so it has a pre alpha outdrive. Got it up to 4000 rpm's for a minute or so when we started hearing strange sounds and seeing smoke appearing from behind the transom along with somewhat of a burnt rubbery fragrance. Quickly dropped the rpm's down but before we could shut the engine off, it quit! Wouldn't turn over, just we?t clunk. Couldn't turn the engine by hand or with a small persuasive bar. After 3 agonizing hours I got the starter out thinking it was the problem but it turned freely. And the engine is still stuck and can't turn the prop either. Engine and outdrive both had/have oil? Batteries had full charge also! Any thoughts???

 

[Bondo]

Ayuh,..... So pull the drive to see what's broken,....

 

[redlinj]

Guess I was hoping someone could tell me what I might expect to find in a situation like this!

 

[Bt Doctur]

If it was severely overheated the motor is seized .if mildly overheated it has a blown head gasket and A/F in the cylinders.
If the drive had no oil left it is seized/ remove the drive to isolate the problem.

 

[stonyloam]

What was your engine temperature? Yeah you have to pull the outdrive. Symptoms sound like you overheated the engine.

 

[redlinj]

The engine did not over heat. Temperature was around 155 f. Oil pressure may have been a little high. Will take the lower unit off and see what happens!

 

[Bt Doctur]

If you are correct with the engine temp then the smoke may have been the rubber exaust components melting from lack of water flow.
The drive could be seized keeping the motor from turning
remove the complete drive, not just the lower

 

[Eric 3.7LX Alpha 1]

Usually a burnt rubber smell is an indication of a failed engine coupler.

You can run the engine with the drive off, stick the garden hose in the water inlet in the bellhousing and try and fire it up. Just make sure it doesn't fall out.

Photo of Fishermark's bellhousing.

 

[redlinj]

OK, outdrive is now out and I can now turn the engine over with alittle help from a large screwdriver. Was gonna try and start it but DAMN, forgot I have already removed the starter so will have to wait a bit. Any suggestions on what to look for next? How do I determine if the engine coupler is shot?

 

[redlinj]

Now that the outdrive is out, the prop will spin freely in either direction. The shaft on the other hand won't move!

 

[Bt Doctur]

how much oil is still in the drive? try removing the 4 top bolts in the cap and post a pic of the remains

 

[Bondo]

How do I determine if the engine coupler is shot?

Ayuh,.... Reach down in behind the motor, where the coupler is, 'n feel 'round,....

Should be plenty of debris,...