Motor mount repair large cracks and voids

[mr gibbs2]

Hello ,need advice on how to proceed took motor out,to replace shift cable hose leak and have cracks on mounts seems to be no rot and dry so ,looking to repair it my self.i know I must grind it all down and open it up a bit but what kind of fiber glass mat should I use how many layers of glass mat any advice would be greatly appreciated

http://imgur.com/a/qoGT5

 

[mr gibbs2]

Photos

 

[mr gibbs2]

bump now ther are photos thanks all

 

[jigngrub]

I wouldn't trust them and would remove and replace them.

If they've got cracks and voids they probably weren't installed correctly in the first place.

The removal, fabrication, and installation looks pretty simple and straightforward.

 

[Woodonglass]

Are you saying that the Wood is still good and the lag bolts screw into the holes with no problems? The interior wood is good to go? I'm not seeing any major issues in the pic?? If there are cracks and crevices then you could dremel them open a bit wider and mix up some resin with some cabosil to thicken it to mayonaise consistency and fill the cracks. That's if everything else is "ShipShape":joyous: Where are these cracks located? Better pics would help. Since you have such great access to the area if there's any doubt about their viability, you might want to consider total replacement.

 

[jigngrub]

Enlarging the pic for a better look:

I say you'd be better off removing and replacing them anyway. I don't like the way the rear bolt holes are too close to the edge.

I would either:
A.

Remove them and enlarge them.

... or:
B.

Center them up better under the motor mount.

 

[mr gibbs2]

Lags were in good and tight no rot ,I doint know if my skill level is there to take out mounts and replace. I was thinking I should grind the area and add mat, glass resin . What kind of mat I'm not sure of.there is one area that is wet on the stringer but drying out .when done gel coat it all . I just need a plane to get started

 

[jigngrub]

Lags were in good and tight no rot ,I doint know if my skill level is there to take out mounts and replace. I was thinking I should grind the area and add mat, glass resin . What kind of mat I'm not sure of.there is one area that is wet on the stringer but drying out .when done gel coat it all . I just need a plane to get started

The cracks and voids in the f'glass of you mm are caused by the wood in the mm getting wet and swelling, wet wood is the gestation period for rotten wood and fiberglass encapsulated wood doesn't dry out.... if you say yours is drying out, then so be it.

If you want to rewrap your mms, go ahead and grind like you said. Grind everything back to good pink glass and grind a 6"-9" area around the mms on the hull. Mix up a batch of peanut butter and fill any cracks or voids that didn't get ground out and fill/stuff your bolt holes with the PB too.

Wrap your mms with 1708 lapping 3" down onto the hull for your first layup. You'll do the same thing for your second layup except you lap another 3" further on the hull. 1708 is a matt backed cloth so it's like 2 layer in one shot.

This will be good practice for you for when your motor mounts rot slap out and fail in a little while, then you can come back and do the whole thing and more over again.

 

[Rickmerrill]

I can't see any cracks from that pic. How about drilling 6 test holes, 3 on each mount, front, back and inside face about 1/4" and an inch deep and see what the chips look like. You can fill em back in with PB or 5200. I don't know what you mean by one area that was wet on the stringer, can we see a pic of that too? Boy, when you figure the glass thickness those back lags are sitting right on the edge. What were they thinking...

 

[mr gibbs2]

I think that I will grind it all out and see what going on ,I had estiments on the repaire and there opinion was both the same they probed the cracks,and said the only crack that was a bit wet was the crack forward of the port side ,the water in the bildge never gets up that high,only since the shift tube started leaking,and the water level was high in the bildge got that high 1 day then I pulled the boat out . Both repair men said that it cracked because the glass was not glassed tight to the the wood typical of a quick production. I f you look at the ends that meet the transum you see they were never covered with any thing ,no rot there first things first clean it up and see ,jigagrub of course I doint want it to fail when I'm offshore trust me when I said there is no rot on the mounts the lags were tight took some muscles to get them out,thank for you input any other advice would appreciated thanks

 

[jigngrub]

when I said there is no rot on the mounts the lags were tight took some muscles to get them out,thank for you input any other advice would appreciated thanks

That's one of the things about wet swollen wood, it really grips a bolt or screw well. Too well sometimes and you end up wringing the head off or snapping the fastener in half before you get it completely out.

We see a lot of fiberglass cracked by wet swollen wood come through this forum, we also see our fair share of motor mount block replacements too... both are common problems.

I'll agree with you and say your wood isn't rotten, yet. But it will be in a matter of time, sooner or later. Like I said earlier, fiberglass encapsulated wet wood doesn't dry out and will rot faster than plain old bare wood.

Re-wrapping your mount blocks isn't going to fix your problem, they'll probably crack again.

I'm not saying your boat is going to blow up and go to hell in a hand basket the next time you take it out, but in a year or two (maybe 3) things are going to start getting mushy in those mount blocks and you'll start to have problems. Then it'll be pull the motor out again and replace the mount blocks, something you could do now to save yourself time and trouble later and that's all I'm saying.

 

[bigdirty]

Just my $.02 here... and i DO i agree with jig, BUT it looks to me like an OMC motor/drive setup, which after another 2-3 years may be even MORE difficult to find parts for and maintain, at which point a re-power with volvo or merc would be in order... if the boat is 'worth it' at that point... Maybe a band aid fix is all it needs right now,and it's not gona make the boat instantly unsafe, or explode...

 

[Woodonglass]

Before you go tearing everything out , I'd advise some core sampling as previously suggested which will tell you if the inner wood is in fact wet and saturated and in need of replacement. While you're at it you should do the same to the Transom. So far, you've not indicated the you've found any major indications of wet swollen wood. The repair guys even said that the glass was poorly done and thats what cause the cracking and they found just a little wetness. As also stated, if it's all dry and good, then fill with 3M 5200 and your're good to go. There's a myriad of reasons for fiberglass layers on the Motor Mounts to have some cracking. Placement of the Mounting holes is not ideal but there may me a reason for that due to the way the motor is configured and how it fits in the space. All of these things need to be taken into consideration. None of us are there and None of us can see any pics that show Major areas of concern. Your descriptions MAY indicate some underlying issues and then again they may not. It's always best to err on the side of safety and to do things right but there's no need to do things that don't need doing either. I'd advise some thorough investigation and evaluation of just exactly what is going on and try and post some better close up pics so we can really SEE what you are dealing with. The factory doesn't always do the best job of glassing in motor mounts and it could be that all they need is some TLC and not total tear out and replacement. If in fact you do have an OMC power train this is another issue too! So Let's get some more info. What boat is this? What motor? What outdrive? What Year? What Size?
We all have our opinions, bottom line is...It's your boat, you're there looking at it, and you should do what seems best for you!

 

[mr gibbs2]

No Title

Yes the omc 460 is still running good and I have lots of parts but ,thinking maybe I should start looking for a Mercruiser ,does any one know ,if the mms line up ,or are close? Maybe I should just do as jigagrub says but set it up for a 454 Mercruiser ,maybe take it all out and start over but I doint know where the mm blocks should be ,I doint mind laying the boat up until nex spring ,I'm using my center consol now, As far as if the boat is worth it ,I think so it a grady gulfstreem ,tanks are good, all around nice boat but farther time always takes it's toll .

 

[zool]

hey mr gibbs, this thread may be of some help if you chose the conversion..

http://forums.iboats.com/forum/engi...tdrives/640807-omc-cobra-vs-mercruser-keyhole

seems quite doable

 

[mr gibbs2]

Good link thanks tomorrow I will take close ups of the cracks

 

[mr gibbs2]

Hello looks like its could be worse any opinion on the photos after grinding thanks. http://imgur.com/a/l6EYJ

 

[Rickmerrill]

I don't think you've cut back enough to be able to tell what's going on. I'd do some more cutting especially where there are still cracks showing and where the glass is not attached to the wood. I think once you get it ground down to where the bond is good you'll have a good idea of what needs to be done. Use whatever tools are at hand (cut off wheel, drill, oscillating tool, chisel) and cut and tear away sections of glass that aren't attached to make quick work of it. Then get some more pics, labeled with location and your comments of what you see. I will say their design left the glasser some pretty tough areas to do his thing correctly.