Engine coupler smoking?

maxum_man

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May 2, 2010
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I have read several posts about after new install of an engine, people have seen white smoke in the engine compartment and smelled burning rubber. I too have this condition after a new install of a 1987 4.3 in my sea ray. I just can wrap my mind around how pulling the outdrive and greasing the inside teeth on the coupler prevents it from damaging the coupler. Any help understanding this would be greatful. Unfortunately, they didnt put the zerk fitting on mine in '87.
 

Bondo

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I just can wrap my mind around how pulling the outdrive and greasing the inside teeth on the coupler prevents it from damaging the coupler.

Ayuh,.... It ain't 'bout greasin' the splines,.... It's 'bout Alignin' the coupler to the gimbel bearin',...

The Smoke comes from the steel piece with the splines inside it, breakin' free of the rubber donut, 'n smokin' itself to death,...

The metal piece inside the coupler, 'n the metal outside of the coupler are bonded to the rubber,....
When either piece smokes, the bond is broken,...
 

maxum_man

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When I installed the new engine, I checked alignment and the tool slid right in like it should. I can put the shifter in forward gear and cannot turn the prop CCW. I would assume that the coupler is still good then? I did put a good coat of high temp engine enamel on it before I put it back in. Think thats whats burning off?
 

Bondo

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There shouldn't be Anything back there hot enough to burn off paint,....
 

maxum_man

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Kinda what i was thinking but i'm open to anything at this point. Im going to pull outdrive today, check alignment again, and grease the splines. I'll let you know in the morning if it helped. Thanks.
 

Maclin

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I am still wanting to ask what makes you think the coupler has spun, have you run it in the water yet? Or just started it on the trailer after the new engine install? If the coupler has spun I suppose it could still act like that at the prop with minimal torque applied. If you really want to check it out of the water then you need to try more leverage when trying to turn the prop in my opinion.
 

JASinIL2006

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One year, when doing my pre-season maintenance, I lubed the coupler from the transom side of the boat (squirting some lube into the splines while the drive was off) rather than by greasing it using the zerk inside the boat.

The first time I took my boat out that year , it started smoking from back there. I posted about it here, and I was afraid I had spun the coupler. As a last ditch measure, I climbed in and greased the zerk on the coupler as I had done in years past. The problem was fixed; I had no more smoking and I didn't have to replace the coupler. That was a couple of seasons ago and everything has been fine since.

Might be worth a try before pulling the motor to replace the coupler...
 

maxum_man

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Alright fellers...
I again put the shifter in forward gear and tried to turn the prop CCW with very little movement. Im a pretty strong guy so I put some torque to it, but not enough to turn the motor! I pulled the drive off and checked the alignment. In my opinion (fireman, not boat mechanic) the alignment is pretty darn good. Heres a link to a video I took while checking it.
https://youtu.be/f6GmHRreGl0
Tell me what you guys think. I dont have the zerk fitting on my old style coupler, so I'm gonna sling a handful in there from the inside before I put the drive back on. I spoke with a local boat shop and that guy just said replace it, but then said I could look through the gimbal and see if there was any rubber debris or melted pieces hanging. I did that too and there wasnt.
What else could make smoke like that with normal operating temp?
 

Grub54891

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I doubt you can spin the coupler by turning the prop, Even the hulk would have a hard time doing that. Even a spun prop hub is very difficult to spin by hand, and the gearsets makes it impossible to do that way. By looking at it from the small hole by the gimbal bearing it can be hard to tell at times also, If you can, mark the coupler with something, like you co when checking a prop, take it for a ride till it acts up, remove the drive and have a look.
 

JoLin

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You should be able to spin the alignment tool using only your thumb and index finger. I can on both my drives. Didn't see you do that in the vid, so hard to tell how much strength you needed to apply to turn the tool.

My .02
 

stonyloam

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New motor install? The alignment looks OK. Could be just burning some crap off of the new exhaust, some oil or grease. Did this happen on the water or when you fired up the engine? The coupler would only smoke if it slipped, on the water under power.
 

maxum_man

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Well...Did I mention I'm a fireman and NOT a boat mechanic? Turns out, the smoke was coming form the PCV elbow on the starboard side of the engine. However, all of the testing so far has been on a garden hose in the yard. I let the engine run for about 10-12 minutes yesterday and the temp gauge started creeping above 175* so I shut er down and ordered a new water pump (I was trying to reuse the older one that looked kinda rough but I see how that went). I am going to change the impeller too. I have new exhaust manifolds as the old ones were cracked.
 

stonyloam

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Yeah a new impeller is a good idea, they should be replaced regularly. Try not to run the engine above 12-1500 rpm on the muffs, because the hose can't supply enough water, and it can possibly overheat. Have fun!
 
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