engine coupler woes

[shaw520]

1980 Thompson Sportmen, w/165 Merc (inline 6)

Repowered her last year, reinstalled fresh engine (aligned) with old coupler, less than 10 hrs later coupler let go. New Sierra coupler installed and aligned, 20 hrs and it let go again, Im sure I had the engine aligned correctly using the alignment tool. ??? Could a worn gimble bearing cause coupler failure?? ..or sloppy u-joints?? I felt some vibration just before she let go. I heard somewhere of a 'steel coupler' Im baffled!! Any suggestions greatly appreciated.

 

[Bt Doctur]

Re: engine coupler woes

All these can affect it
loose /rotted front motor mount stringer
bad rear bushings
rotted transom allowing flex
Did you replace the rear bushings??

 

[Bondo]

Re: engine coupler woes

1980

Ayuh,... I'm guessin' transom/ motor mount flex...

 

[shaw520]

Re: engine coupler woes

Ok then,..Im pulling the motor this week...and I'll put those transom bushings on the list of things to replace this time around, along with;
gimble bearing/housing
u-joints
and of course,..coupler

Next question, are there any reasons why I SHOULDNT use another Sierra Coupler ??

thanx

 

[Bt Doctur]

Re: engine coupler woes

Dosent matter, put titaninum in and it wont matter if the issues described above are present.

 

[Bondo]

Re: engine coupler woes

Next question, are there any reasons why I SHOULDNT use another Sierra Coupler ??

Ayuh,.... Personally,... I've got Alotta hours on 1, without complaints...

 

[shaw520]

Re: engine coupler woes

good stuff here boys, thank you.

hmm,... any way to torque test the engine mounts while dry docked...

(torque test,.. ha I made that up!)

 

[Bt Doctur]

Re: engine coupler woes

Beat you to it. Here is the torque test

 

[shaw520]

Re: engine coupler woes

 

[meesh]

Re: engine coupler woes

I'm on my second season with a sierra coupler. No problems.

 

[shaw520]

Re: engine coupler woes

I'm on my second season with a sierra coupler. No problems.

Good to hear,.. really didnt wanna have to cough-up the xtra 200 beans for a merc job.

 

[777memaw]

Re: engine coupler woes

I had 3 couplings go out in one season b4 I found out the transom was out. Have someone stand on the outdrive and bounce look and see if there is any movement where the housing bolts on to the transom. If there is any give the transom the transom is rot.

 

[shaw520]

Re: engine coupler woes

I had 3 couplings go out in one season b4 I found out the transom was out. Have someone stand on the outdrive and bounce look and see if there is any movement where the housing bolts on to the transom. If there is any give the transom the transom is rot.

Ok,.. did that and there is some flex in the transom!,... but how much is acceptable,..? oh boy,.. this is not good Can I ad some stringers to the transom, how to strengthen it?

 

[Bt Doctur]

Re: engine coupler woes

Let me rephrase that for you
"How can I add stringers to make the peat moss in my transom hard again"

 

[shaw520]

Re: engine coupler woes

Let me rephrase that for you
"How can I add stringers to make the peat moss in my transom hard again"

...exactly,... thank you

 

[shaw520]

Re: engine coupler woes

Two layers of 3/4 ply laminated,... some aluminum angle,.. duct tape,.. gorrila glue ??? Any basic ideas??

 

[Bt Doctur]

Re: engine coupler woes

Downside ,if you strike something very hard ,you`ll tear the transom off the boat.if you grab a hole shot ,you`ll tear the upper transom part away.Either case leaves VERY,VERY BIG HOLE.
There is no quick way, remove engine, transom housing , inner fiberglass panel ,all the wet, rotted remains of what used to be plywood, cut new material glass in place, use the cutout and holes as a guide to recut the new holes,reinstall everything.

 

[Bondo]

Re: engine coupler woes

Two layers of 3/4 ply laminated,... some aluminum angle,.. duct tape,.. gorrila glue ??? Any basic ideas??

Ayuh,... It takes about 2 layers of 3/4" plywood to REPLACE the Rotten wood...