spun coupler vs. spun prop hub

[cimy3]

Hello. Boat is a 1989 240 Thompson with a 1989 Mercruiser Alpha One with a 5.0 Litre Engine (305 CID). Transom Serial number is OC512260. Drive Unit is OC496777.

Here is what happened...out on the lake trolling at 2mph (did not hit anything) and all of sudden I hear a high pitched whine. I run to the back of the boat and notice nothing out of the norm, so I returned it to neutral and turned off the motor.

Started it back up and it would shift in to gear fine, but the boat would not move.

Gotta tow back into port.

At home, I put on the hose to see if the whine was still there in neutral and it is. Again it would shift in gear, but would not turn the prop.

While the engine was off, I put it into forward gear and turned the prop by hand clockwise and it was clicking (and acting as if it want to connect and lock in).

Any thoughts?

thank you, Ray

 

[Haut Medoc]

Re: spun coupler vs. spun prop hub

The first & easiest way would be to put on a different prop....
If the coupler were bad it would over heat.....
However, usually you will get something out of the prop, at least enough to crawl home if it were the hub.....
I would test to see if it was going into gear by shifting into fwd & trying to turn the prop ccw......
Of course this is performed with the engine off.....
If it will not lock in gear you either have cable problems or internal drive problems.....
The next step would be to pull the drive & see if it will go in gear....

 

[cimy3]

Re: spun coupler vs. spun prop hub

Just checked with the engine off....put into forward gear and when spinning the prop ccw it locks....now, what should i check next?

 

[Uraijit]

Re: spun coupler vs. spun prop hub

can you get it to shift into forward AND reverse?

 

[Bondo]

Re: spun coupler vs. spun prop hub

out on the lake trolling at 2mph (did not hit anything) and all of sudden I hear a high pitched whine. I put on the hose to see if the whine was still there in neutral and it is.

Ayuh,.....

I'd pull the Drive,+ inspect the U-joints, Gimbel Bearing,+ the Input shaft,.....

My WAGuess is,....
You need a New Shaft,+Coupler....

The shaft splines,+ coupler haven't been properly Greased over their life times....

Trolling is about as Hard as you can get on the shaft,+ coupler,... Possibly Worst than WOT Starts...
The constant loading,+ unloading,+ negative loading of the splines just Tears'em Up....
Every Wave will do it,... How many Waves have you trolled thru,..?? Or With,..??

Gotta keep'em Well Greased......

 

[chiefalen]

Re: spun coupler vs. spun prop hub

Did it overheat? If yes coupler. If not prop spun. My coupler went i didn't go nowhere.

Won't hurt to pull the outdrive but why if its the prop.

How the oil look in the outdrive?

Woa could be a lower cable went. I just reread the first post. I bet it's the lower cable.

 

[cimy3]

Re: spun coupler vs. spun prop hub

Let's see.....no, it did not overheat. I can shift into forward and reverse with no clunking, but it does whine and the prop does not spin.

I haven't checked the oil in the drive yet....tomorrow for that one. It would be nice if it was the lower shift cable vs. a coupler.

Thank you all for the suggestions.

Ray

 

[chiefalen]

Re: spun coupler vs. spun prop hub

We ain't gonna know nothing till he checks that oil in the out drive.. If it did not overheat it ain't the coupler. Thats a fact.

I just can't get my head around that the boat shifts. He says it goes in gear the prop don't turn.

But it locks up when he is in gear turning by hand.

That stikin lower shift cable how not working if it shifts into gear?

This is a puzzle?

Got a busted gear! Teeth eaten up! Lower pinion gear maybe! Can't be the upper pinion cause he would overheat!

Thats the whirling or whining noise.

 

[bolo78910]

Re: spun coupler vs. spun prop hub

friend was having the same problem a few weeks ago, turn out to be the upper unit was shot.

 

[Uraijit]

Re: spun coupler vs. spun prop hub

We ain't gonna know nothing till he checks that oil in the out drive.. If it did not overheat it ain't the coupler. Thats a fact.

I just can't get my head around that the boat shifts. He says it goes in gear the prop don't turn.

But it locks up when he is in gear turning by hand.

That stikin lower shift cable how not working if it shifts into gear?

This is a puzzle?

Got a busted gear! Teeth eaten up! Lower pinion gear maybe! Can't be the upper pinion cause he would overheat!

Thats the whirling or whining noise.

Sounds like he shut it right down within a few seconds of hearing the noise. Generally it would take longer than that for an overheat to take place. I wouldn't rule out the coupler without visually verifying that the engine is not spinning the input shaft to the drive. Takes 2 seconds to check...

 

[achris]

Re: spun coupler vs. spun prop hub

Takes 6 minutes to pull the drive and look inside.... Use a small torch
Sounds like coupler to me. Shutdown immediately would be too soon to see any overheat. Putting in gear on the trailer, with no load, wouldn't prove anything either.

Spend 6 minutes... If nothing else, you'll have a chance to grease the splines and unis.

Chris..........

 

[chiefalen]

Re: spun coupler vs. spun prop hub

Won't prove nothing on the trailer cause the coupler might still turn. Got to be under load. Just don't want the guy to have to pull the motor for nothing it's a byatch.

My coupler went the temp gauge shot right up in 5 seconds no s--t.

The water pump shaft went same thing.

I was only doing 3500 rpm.

He was trolling what 1000 rpm.

My shaft turned easy on the trailer in gear with the coupler gone.

Yea pull the out drive look at the shaft. Easy to do and you get to grease it real good.

 

[CAPTKEV85]

Re: spun coupler vs. spun prop hub

sounds like the hub. happend to me i went to plane off and then the boat stopped, and i heard a whinning noise at the back of the motor. i wished it was the prop. much cheaper and easier to replace.

 

[cimy3]

Re: spun coupler vs. spun prop hub

Took it to my mechanic today and the finding is...... the coupler is shot. Thanks for your help in diagnosing the problem based upon the description.

This is a great site.

Thank you all.

 

[Fishermark]

Re: spun coupler vs. spun prop hub

Takes 6 minutes to pull the drive and look inside.... Use a small torch

When I first read that, I thought you were talking about the acetylene torch - the "red wrench."

Then I realized that on your side of the pond that's probably what you call a flashlight.

I just don't want people thinking you need to burn the outdrive to get it off.

 

[Bondo]

Re: spun coupler vs. spun prop hub

Takes 6 minutes to pull the drive and look inside.... Use a small torch

Ayuh,...
I brought the same quote down to post,+ was going to mention that the torch is a Flashlight on This continent,....

When I first read that, I thought you were talking about the acetylene torch - the "red wrench."

And,...
That a set of "Blue Tip Wrenches" in My world.....

 

[achris]

Re: spun coupler vs. spun prop hub

When I first read that, I thought you were talking about the acetylene torch - the "red wrench."

Then I realized that on your side of the pond that's probably what you call a flashlight.

I just don't want people thinking you need to burn the outdrive to get it off.

Actually there are 2 ponds between me and the. Either way you go ...

So for my northern freinds, a flashlight it is.... Same as we call Petroleum 'Petrol' and you lot call it 'gas'... Gas is what we light the bbq with

Cheers.............

 

[cimy3]

Re: spun coupler vs. spun prop hub

The mechanic found that the front right engine mount was the problem of the worn coupler. Thanks again for all of your insight.

Ray

 

[Bondo]

Re: spun coupler vs. spun prop hub

Thanks again for all of your insight.

Ayuh,...

And Thank You for taking the time to come back to tell Us the outcome.....