Checking coupler

[Datimm]

I have a 3.7 mercruiser out of the boat now and before I put it back in I would like to check the coupler to know if it's good or not. Can someone tell me how?

 

[Bt Doctur]

the splines should have sharp square corners, not pointed

 

[Datimm]

Hows this coupler look?

I was told the condition of the coupler can be told by the condition of the splines. This is the first one I have seen, can anyone tell me how it looks.

 

[Bt Doctur]

looks ok to me a bit light on the grease

 

[GA_Boater]

It's isn't just the splines. The rubber can give up the ghost with perfect splines just like a spun prop hub. We have more bad coupler questions about the stink and smoke when the rubber separates than bad splines.

Clean the cobwebs out before you grease it up.

 

[Bondo]

It's isn't just the splines. The rubber can give up the ghost with perfect splines just like a spun prop hub.

Ayuh,..... Can't see much of the rubber, but what can be seen, don't look to healthy,.....

 

[harringtondav]

The splines look OK, but the aluminum core hub looks like it has some cracks. Since you're into it this far, I say replace it. What year is your 3.7? I poked around looking for a good price, but haven't seen one that looks like your pic.

 

[Datimm]

It's a 1986.

 

[harringtondav]

I don't know if this is your coupler, but it matches your vintage. https://www.summitracing.com/parts/...7TQk0zidSZL_aleyY0CiRogvT9NxehoC5jAQAvD_BwEIf the price pushes you off, grease yours up good as mentioned above. Prop whacks take out most couplers. Avoid them and you may be good for some time.

 

[Datimm]

Most definitely the lowest price I have seen yet, thank you. I am going to cross my fingers and run it how it is. Worst case I can pull the engine in less then a hour, so I can suck it up and fix it if I have to.

 

[stonyloam]

I was goin to say change it, till I saw the price LOL! I think you have a good plan, just make sure your alignment is correct and grease it really well.

 

[CamaroMan]

That's fine, it's when the tips are pointed it needs replacing.

Use EP grease for splines and u joints .. Lucas red n tacky has the EP additive and good for trailer bearings too.

Oops, didnt see hairline cracks. Merc uses the same coupler from 110 to 260, on ebay for 92 bucks.. 2 pc rear main that is, 86 is borderline to single rear swap l, u can check bolt pattern to confirm your model.