Engine mount lag bolts pulled out

[Mmmboating]

When hoisting out motor the lag bolts pulled out of the engine mount stringer. The lag bolts were corroded and iside the holes the wood that is encased in fiberglass was really soft and mushy. My question is can I use git rot or rotdoctor to fill the holes and screw new lag bolts in? The boat is a 17 ft bowrider with 2.3l omc cobra. The reason I was pulling the motor was to replace stripped engine coupler probably caused by the loose engine mount lag bolts.

 

[Trooper82]

Re: Engine mount lag bolts pulled out

If the motor mounts are worm dirt, then I would suggest sampling the stringers fore of the motor mounts and the transom too for dry or wet wood. Take a drill and drill into them see if it comes out dry or wet. Be careful to not penetrate the hull. Rot starts towards the bottom and works it's way up most of the time.

I am not familiar with either of these products personally but have seen posts on here and they usually are against this type of repair. Really depends on the situation. Can you put up some pics so we can see what you are seeing?


Oh, and Welcome to Iboats!

 

[StevenT]

Re: Engine mount lag bolts pulled out

It sounds highly suspect of rotten wood. Your probably looking at a rebuild of deck, stringers, engine mounts, and transom. Do you have any soft spots on the deck? The problem with wood rot is it spreads fast.

 

[Woodonglass]

Re: Engine mount lag bolts pulled out

To answer your question...Yes you can use those products. And yes they might fixe the problem to some degree. The real question is...Should you use these products? Answer...NO! They will not adequately and permanetly fix the issues you have. I highly suspect if you do further investigation, as others have eluded to, and I HIGHLY recommend, you will find the stringers, deck and transom have soaked wood, and rot issues as well, which can make your boat and unsafe vessel. A quick and easy fix is prolly NOT the best idea for your boat.

 

[fat fanny]

Re: Engine mount lag bolts pulled out

It looks like you have two bad cards in your hand OMC and rotted stringers! A real good evaulation of your rig is in order. As stated above probing the stringers and transom with a drill bit set to @ least an inch and start drilling you may find the work ahead of you may well exceed the value of your rig and with a power plant with a manufacturer no longer in buissness may not be a good finacial investment!

 

[Mmmboating]

Re: Engine mount lag bolts pulled out

The only wood in the boat is the transom and the engine mount box/stringer. The rest is Fiberglas over foam. Transom is solid and no other soft spots except for the sheet of plywood that covers the fuel tank.

 

[jigngrub]

Re: Engine mount lag bolts pulled out

Have you core sampled the transom down low, or just tapped on it?

Using the git-rot or rot doctor is just going to prolong the agony of the task at hand by a couple of months. This means you'll have to spend the money for the temp fix and still have to fix it right in a short time.

Do you really want a mush base and epoxy filler holding your motor to your boat?

Wouldn't you rather be boating in a structurally sound seaworthy boat instead of one that could be considered a safety hazard to you and your passengers?

I suggest fixing your boat right for peace of mind instead of slapping a band-aid on it.

 

[Mmmboating]

Re: Engine mount lag bolts pulled out

any ideas how to fix the base for the mounts? i have never done any fiberglas work before. should i cut the top of the box off then dig out the rotten wood and fiberglas the top?the wood i n there just seems to me as something that will also fail again. i haven't core sampled the transom but did poke around with a screwdriver and it is solid. the back mounts are solid as well.how much torque is on the two front mounts or do they just hold the motor down when going over a big chop? this is my first boat and i would be happy if i got two more seasons out of it then probably upgrade. thanks for the info keep it coming please.

 

[Mmmboating]

Re: Engine mount lag bolts pulled out

 

[JDA1975]

Re: Engine mount lag bolts pulled out

the wood is what the lag bolts grip into, without it the fiberglass would break under the stresses...while it is not at all optimal you could redo the mounts by themselves..I did in this thread...

http://forums.iboats.com/showthread.php?t=563341

Like I said that is nowhere near an optimal repair, you should check all surrounding wood for rot and repair all that as well

 

[Mmmboating]

Re: Engine mount lag bolts pulled out

That repair is what I need. Looks similar to mine. Did you just cut off the top then take out rotten wood and replace and fiberglass?

 

[tpenfield]

Re: Engine mount lag bolts pulled out

When hoisting out motor the lag bolts pulled out of the engine mount stringer. The lag bolts were corroded and iside the holes the wood that is encased in fiberglass was really soft and mushy. My question is can I use git rot or rotdoctor to fill the holes and screw new lag bolts in? The boat is a 17 ft bowrider with 2.3l omc cobra. The reason I was pulling the motor was to replace stripped engine coupler probably caused by the loose engine mount lag bolts.

Welcome to boat restoration. You will be pulling the rot out of those mounting stringers and re-filling them with new material.

Git-rot is for dry rot, and it sounds like you got wet rot.

 

[JDA1975]

Re: Engine mount lag bolts pulled out

no I removed the entire motor mount and the surrounding rotten wood, then built new motor mounts using 2X6 instead of hollow plywood box that was originally there and then glassed it in, go as far as you can and remove as much rot as you can, be sure the new material is well encapsulated, coat wood with resin, then some glass..then install and add more glass to tab them in...I used a 1.5 oz CSM followed by 24oz woven roving to tab them in and then did 1.5oz CSM 6oz woven alternated to add strength and give it less of the glass pattern...

 

[Woodonglass]

Re: Engine mount lag bolts pulled out

I cannot stress enough that poking the transom with a screw driver is not an advisable test for your transom. You should drill core samples to ensure that it is sound and seaworthy. If you go to the trouble of replacing the motor mounts and the transom is bad your efforts will have been in vain. It only takes a few minutes to core sample the transom and if you find dry shavings then all that is required is to fill the holes with 3M 5200 sealant and you're good to go. My mamma said, "If it's worth doin, it'w worth doin right!"

 

[jigngrub]

Re: Engine mount lag bolts pulled out

Where is the water coming from that rotted this wood? Is it storm water from being left outside and uncovered? Or is it coming through the hull or transom while it's being used?

Core drilling down low on your transom on bothe sides of the outdrive "key hole" will let you know if your transom is leaking and if your wood is wet. Core drilling down low on your other motor mount blocks will let you know if they're wet. If any of that wood is wet you'll have some nice rot produced over the winter and will really kick in with warm spring temps.

 

[Mmmboating]

Re: Engine mount lag bolts pulled out

I think the in the mount boxes the water came from me beaching the boat after the anchor let loose during a storm. The waves came over the stern and partially flooded the back half of the boat overnight. The lag bolts were not sealed so the boxes must of been filled with water. This was back in July. I drilled the transom and it is good.

 

[tpenfield]

Re: Engine mount lag bolts pulled out

These things do not rot overnight and it is probably due to moisture seeping in over a long period of time - years.

The thing about boat construction is that during the hull layup stages, the manufacturer seals things up pretty good with glass & resin. Then it goes to the next step in the process where they drill holes in everything.

Those stringers had the hole for the lag bolt drilled in them, and moisture from the daily condensation cycle is probably what seeped into the wood over a long period of time. Also, once the wood in a boat's structure absorbs water, it has no good way of getting rid of it.

 

[Mmmboating]

Re: Engine mount lag bolts pulled out

Yes the lag bolts were never sealed or siliconed in. I am going to cut the box open and investigate. probably rebuild it and go from there.

 

[jigngrub]

Re: Engine mount lag bolts pulled out

I would cut that box off flush with the hull and grind back to good glass, then embed a new solid block in PL adhesive and glass it back into the hull. Make sure your new block is kiln dried regular untreated wood, pressure treated wood will be wet and theadhesive and resin won't penetrate or stick to it. Then whe you reinstall the bolts, drill your holes and screw the lags down... the remove them and squirt some 3M 5200 into them and put a little on the threads of your lags and reinstall.

 

[Mmmboating]

Re: Engine mount lag bolts pulled out

Ok I've cut the mount boxes now I'm going to replace the wood. Question is can I use pressure treated wood or am I better of using a 4x6 chunk of fir? And also will the home depot bondo epoxy and fiberglas cloth or mat work or should I go with another product.