Is my transom rotting or human error?

[dazzy]

I have run into an odd problem. There is a gap between the gimbal housing and the hull, now before you jump to rotten transom hear me out. I've been reading a LOT and from very reliable people on these forum they say it's pretty much impossible for those bolts (pictured) to come loose.

From what I understand the square bit on the back of the built in "washer" goes into the transom plywood allowing you to tighten the nut with the nylon insert from the inside. From what I can see with the picture (can't see it with motor installed) the nut end of the bolt is against a metal flange on top of the fiberglass. Am I understanding how it works wrong? I just don't understand how the bottom of the motor could be tipping out even if there was no transom installed.

I have done the weight test, and if it moves at all it's no more than 1/16th of an inch. Previous owner (I just bought it a couple weeks ago) is no help. So is my transom going or did someone just not get them tight when they put it back together?

There was a pretty heavy bead of normal silicon around the entire gimbal to transom, is the gasket supposed to take care of that or should I put 5200 at the end of whatever happens?

(mercruiser part #55989A8)

 

[jbcurt00]

Re: Is my transom rotting or human error?

Post some pix that aren't such close ups, showing an entire side of the gimble housing, and possibly reshoot the 1st & 3rd pix. When you open them, they're blurry....Possibly the 2nd too.

To the best of your knowledge has the motor been out? And has there been any previous transom work done?

The motor has adjustable mounts to aid in alignment w/ the outdrive, doesn't it?

If the front of the motor is too low, the lower outside part of the outdrive would need to be tipped away from the transom to get the alignment right for the splined shaft & coupler, correct?

Soft motor mounts would also cause misalignment thru the keyhole causing a gap.

An improperly installed outdrive & improperly tightened bolts also seem likely...

 

[dazzy]

Re: Is my transom rotting or human error?

Post some pix that aren't such close ups, showing an entire side of the gimble housing, and possibly reshoot the 1st & 3rd pix. When you open them, they're blurry....Possibly the 2nd too.

To the best of your knowledge has the motor been out? And has there been any previous transom work done?

The motor has adjustable mounts to aid in alignment w/ the outdrive, doesn't it?

If the front of the motor is too low, the lower outside part of the outdrive would need to be tipped away from the transom to get the alignment right for the splined shaft & coupler, correct?

Soft motor mounts would also cause misalignment thru the keyhole causing a gap.

An improperly installed outdrive & improperly tightened bolts also seem likely...

To the best of my knowledge the motor has not been out in the last 5 years (previous owner)
Same with transom work. I did the tap test and every inch of it sounds solid and the same (I know that's not completely reliable)
The front of the motor being too low sounds correct to me, but not 100% sure, this is my first inboard.

When I first got it a couple weeks ago I had to change the shift cable, everything went back together smooth (not sure if that's an indication of alignment). I haven't put it in gear yet, was taking it out to check the kill switch when I noticed the water coming in. Being 30+ years old anything is possible I imagine.

Thanks for the help, I'll get better pics in the light in the morning

 

[jbcurt00]

Re: Is my transom rotting or human error?

When I first got it a couple weeks ago I had to change the shift cable, everything went back together smooth (not sure if that's an indication of alignment). I haven't put it in gear yet, was taking it out to check the kill switch when I noticed the water coming in. Being 30+ years old anything is possible I imagine.

This was an important detail

You couldn't tell where the water was coming in? I doubt it, but not from somewhere else, & not anywhere immediately around the keyhole?

 

[Watermann]

Re: Is my transom rotting or human error?

Hi Dazzy, welcome to iboats.

First off you should always post up the information on your boat: year, make, model, motor and sterndrive info.

You have a problem for sure if there's a gap between the transom and and gimbal mount. It should be flush and only use the gasket. The silicone is a bandaid that someone decided to slap on to try and stop the intrusion of water. It won't work. The only way to know what lays at the root of the problem is to tear it down.

You may get more replies posting in the mercruiser thread when dealing sterndrive problems.

Good luck!