4 month old coupler blew today

Well as I was cruising along the engine raced. I thought the prop. But the temp went up 20 degrees the first time it raced. So I knew it wasnt the prop.

So, I waited a few mins. Then put it in gear and I could go idle up to 1100 RPMs fine. Over 1500 RPMs and it would race.

But at 1200-1500 RPMs it made the whole boat shutter and I could hear the coupler slipping and turning (inside itself). This whole time though I never smelled not one bit of burning rubber. I tried to fell the coupler but could only feel one spot of it without taking the whole doghouse off. It felt smooth and normal to me.


This coupler is new in June last year. I bought it when I installed a new engine. I bought the alignment bar, watched the videos and read on here. Followed the manual also. I got it perfect where it would slide in and out with no friction. Rotated 90 degrees and repeated. Perfect.

I took the drive off about 2 months ago to replace the bellows and when I put it back on I checked the alignment to see if it was still true and it was only the very smallest bit off. But I still got it perfect again.

So what could cause this. Rotted transom, engine mounts rotted? But if any of that was the case would it not cause the alignment to be way off?

I haven't taken any samples yet but when the engine was out I checked the transom very good because I want to install underwater lights. It looked great to me.

Re: 4 month old coupler blew today

So what could cause this. Rotted transom, engine mounts rotted? But if any of that was the case would it not cause the alignment to be way off?

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Ayuh,... A rotten, Flexing transom will be in alignment at rest, 'n Way Out under power....

Did you Grease the splines up real good,..??

Re: 4 month old coupler blew today

Yea, and I felt grease all over the place when I felt the coupler. I guess Ill have a better look at the transom when I lift the engine to change the coupler. This def sucks. I just got this 2 month long interior project finished and now this. Thats how it goes though.

Re: 4 month old coupler blew today

LAC_STS said:

Yea, and I felt grease all over the place when I felt the coupler. I guess Ill have a better look at the transom when I lift the engine to change the coupler. This def sucks. I just got this 2 month long interior project finished and now this. Thats how it goes though.

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Ayuh,... Does it appear to be the rubber ripped apart, or the splines stripped,..??

Re: 4 month old coupler blew today

My plan tom is to get a mirror and take the doghouse off and get a good look at it.

I couldn't see it today but I did feel it. It did not feel like the rubber was blown out.

But the sound that I was talking about was def a rubber sound. It didn't sound like metal.

Re: 4 month old coupler blew today

I just went to get the boat out of the water. It's raining here so I didn't get a chance to look at the coupler.

But guess what I saw when was flushing the engine? The pivot pin that holds the pivot housing on (there's 2, one on each side), the starboard side pin was cockeyed looking. I just happened to notice it.

So I lifted up on the drive and it wasnt just loose it was like the pin was just sitting in there. When picked up on the drive I could see it (pin) moving back and forth.

I did remove the pivot housing when I did the bellows but I've had the boat out4-5 times since then.


So with this pin being loose I'm sure it made the alignment WAY off right? I mean I'm lucky the whole drive didn't fall off, no?

Re: 4 month old coupler blew today

I just want to reply so i can see what you found... and to say, your WAY to calm about it....

Re: 4 month old coupler blew today

Phfantasm said:

I just want to reply so i can see what you found... and to say, your WAY to calm about it....

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I just got done (almost done actually lol) with the entire interior. Headliner, seats, carpet, hardware and all.

Its been one thing after another with the interior and the boat in general lately. Thats just how its been lately. I dunno. Thats a boat though.


My plans are to verify the coupler is gone with a mirror tomorrow. Then Im gonna take the boat home from the marina and use my friends set of A frames and a chain hoist to lift the engine. Im not gonna take it all the way out of the boat. Im just gonna disconnect everything (after removing drive) and lift the engine up so i can get to the coupler. And while Im at it Im gonna install new flappers.

I have been wondering if I will beb able to change the coupler by just moving the engine forward. Theres about a foot of room in between the front of the engine and the engine compartment wall.

But I guess it wouldn't be that much easier. I dunno

Re: 4 month old coupler blew today

LAC_STS said:

I have been wondering if I will beb able to change the coupler by just moving the engine forward. Theres about a foot of room in between the front of the engine and the engine compartment wall.

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if you are going that far, disconnecting everything to move the engine a foot forward, why not just get it all the way out??

that way you can get in the bilge, tighten all the transom nuts, y-pipe bolts, plenty of room to do the flappers and inspect anything else that may need attention

BTW, you did put loctite on the hinge pins, right?? - i use blue and torque to 100 lb/ft

Re: 4 month old coupler blew today

Thats what I was thinking dubs. Im sure there is tons of stuff I would like to look at, fix and/or clean while the engine is in the air. My steering assy on the inside of the transom has been shaking when I steer the wheel any faster then slow. I have been trying to figure out what exactly to tighten because its not where the steering assy attaches to the transom, thats solid. The assy is firmly attached to the transom but the rod or whatever its called is loose or something. I dunno. I havent been able to get to it. With the engine out though I should have great access to it.

If I remember correctly the manual said to use "thread sealant". I used the white stuff made by Permatex. Ill have to look exactly at the exact kind but I have since come to the conclusion that the stuff I used was just sealant for threads that might go into a water jacket area or something. Im thinking its not like Loctite red or blue.



Another thing on a side note is that I have replaced the lower shift cable a few months ago but it was still a little more than the 2 pounds suggested. The control/shifter box was the original 1989 one. I bought a brand new version BRP one and man it shifts with 1/4 lb of force. I dont even know if it would register. That was one good thing that worked out great. The interior is looking good too. Im gonna have to take some of these brand new panels off so I dont mess them up when Im doing this coupler. Ill post some pics when I get some.

Re: 4 month old coupler blew today

when i changed my coupler... i lifted the engine, moved it a few feet foward and twisted it on the hoist chain and changed the coupler.... just a few hours of work total

Re: 4 month old coupler blew today

My steering assy on the inside of the transom has been shaking when I steer the wheel any faster then slow. I have been trying to figure out what exactly to tighten because its not where the steering assy attaches to the transom, thats solid. The assy is firmly attached to the transom but the rod or whatever its called is loose or something. I dunno. I havent been able to get to it. With the engine out though I should have great access to it.

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Ayuh,... Just a guess,...
The tube the end of the cable goes through, tends to get corroded,...
If the P/S is fightin' it, it might be the problem...
Another thing,..
I believe the flats of the P/S valving shaft have to be aligned, Up, 'n down, I believe...
Look in the manual, or maybe somebodyelse knows...