Motor Mounts for a 4.3L Merc

[jasonbrodsky]

I am replacing my motor and have noticed that the motor mounts were barely attached to the boat. The screws holding it had stripped or had noting to bite into. Any ideas.

I was thinking of attaching some 2x4's to the bielge area and fiber glassing them to give additional strength. Does that sould like a good idea?

 

[Woodonglass]

Re: Motor Mounts for a 4.3L Merc

If the mounts are rotting, I'd suspect you could have other issues as well. What kind, Age, Size of boat is this? Any soft spots in the deck/floor? A quick fix of the MM's is not recommended until you know for sure that the rest of the boat, i.e. stringers and transom are seaworthy. JMHO

 

[wellcraft-classic210]

Re: Motor Mounts for a 4.3L Merc

Were they lag bolts going into wood with figerglass over them? If so it sounds as if they may be rotted. Best way is often to replace the wood & repair the fiberglass removed in the process.


As woodonglass suggested above a quick fix is not recomended.

Check out the restoration section if this forum for some folks doing these sort of repairs & working with wood & fiberglass.

 

[jasonbrodsky]

Re: Motor Mounts for a 4.3L Merc

Were they lag bolts going into wood with figerglass over them? If so it sounds as if they may be rotted. Best way is often to replace the wood & repair the fiberglass removed in the process.


As woodonglass suggested above a quick fix is not recomended.

Check out the restoration section if this forum for some folks doing these sort of repairs & working with wood & fiberglass.

The lags bolts were going straight into fiberglass.. The engine mounts themselves are fine. I am justrying to re ataach them to a solid surface with something for the lag bolts to bite into. There is no wood at all that they were initially attached to. Someone in the past either removed the wood and attached straight to fiberglass or something else.

So my question is simple. can I attach wood to the fiber glass and attach the mounts to the wood?

 

[jasonbrodsky]

Re: Motor Mounts for a 4.3L Merc

If the mounts are rotting, I'd suspect you could have other issues as well. What kind, Age, Size of boat is this? Any soft spots in the deck/floor? A quick fix of the MM's is not recommended until you know for sure that the rest of the boat, i.e. stringers and transom are seaworthy. JMHO

I have a '93 Manta Ray, 18.5ft..

The only bad spots, as far as decking were the back seats. That are totally rotted out and are rebuilding with some MDO. I am creating a built in cooler where the live well used to be. The rest of the deck is fine.

I have been rebuilding the motor and lower stern unit for the last few weeks and I am ready to put motor back into the boat when I noticed that the motors mounts had been originally attached straight to fiberglass around the bilge pump area. The holes will not support the vibrations from the motor to keep the alignment correct. The mounts themselves are in perfect condition.

So again, my question.. What is the best way to repair these motor mounts, or secure them to the boat?

 

[wellcraft-classic210]

Re: Motor Mounts for a 4.3L Merc

Jason
Many boats were fabricated with wood bedded in resin over the hull. That said is the fiberglass you refer to hollow or solid? Does your boat have wood elsewhere? ( if so it most likely had wood stringers originally) Can you post a few pics?

I am attaching a few pics of a port stringer replacement on a 1988 merc 5.0 -- lots of ways to approach this / posting these so you can compare this to yours. As you may be aware the finished height of the stringer is fairly critical and it must bear weight. ( The force is mostly downward but vibrations etc. do place some forces in other directions. )

The main concern is that the motor position must stay constant and be properly aligned which will in turn avoid mechanical damage / problems on the rear coupler & drive components.

 

[Woodonglass]

Re: Motor Mounts for a 4.3L Merc

Without pics is very difficult to give you the proper advice. Post some pics and I'm sure we'll be able to guide you to the correct solution.

 

[jasonbrodsky]

Re: Motor Mounts for a 4.3L Merc

Without pics is very difficult to give you the proper advice. Post some pics and I'm sure we'll be able to guide you to the correct solution.

I will post some pics tonight.. Question.. If I remove the plywood currently on the deck, should I be able to see the stringers?

My hole thing is that the holes that the lag bolts made in the fiberglass of the bilege area is just worn out and I want to fix it properly so the engine sits tight and perfect.
Is there any videos on creating stringers?

 

[Bondo]

Re: Motor Mounts for a 4.3L Merc

My hole thing is that the holes that the lag bolts made in the fiberglass of the bilege area is just worn out and I want to fix it properly so the engine sits tight and perfect.

Ayuh,.... We all know What you Want,...

We're all tryin' to tell ya that motors usually aren't lag bolted to JUST fiberglass...
Matter of fact, I've Never seen it...

It sounds like you've got Bigger problems than you Think you have, 'n We're tryin' to steer ya Right....

 

[jasonbrodsky]

Re: Motor Mounts for a 4.3L Merc

Sorry.. Just alittle frustrated.. I do appreciate everyone's help.

I thought the same thing when I initially saw the motor mounts lag bolted to fiber glass.

So, I guess while I have to still rebuild the back seating, I guess I should pull up the plywood decking and really check out what is going on underneath. Right? I do know the transom itself is in solid condition. The floors on the other hand i will let you know. I have never made stringers before.. Is there some place that I can watch a video on how to? I am a serious visual guy..

Do they make a stringer system that can be tied into the decking for the motor mounts?

 

[wellcraft-classic210]

Re: Motor Mounts for a 4.3L Merc

Lookin forward to your posting of the pics as its very hard to offer good/ detailed advise to you without them.
The engine stringers are directly under your motor mounts -- Thier are floor stringers under your floor. Portions of the floor may have to come up to get to the engine stringers.

I suggest AGAIN that you brouse the boat restoration section of this forum to see what may be involved. Might be smarter to do before you do a tear down. Mostly pics with text -- not videos --lots of great usable info. Better than videos in some ways. One example link pasted here-- http://forums.iboats.com/showthread.php?t=536467

As you will see -- People often use wood cut to fit and bedded with epoxy & fibergass cloths to fix these-- Thats usually "the system" for older boats when they were originally built and again to repair them. Newer boats often have composite materials in place of wood which eliminates these problems.

 

[jasonbrodsky]

Re: Motor Mounts for a 4.3L Merc


OK. Here are photos of my motor mounts. The area they have been attached to is solid. I took a core sample and the wood particles that came out were dry as normal. The area seems solid too. Mh problem is that past persons didn't use the correct amount to of bolts to tie down the mounts and the holes have been oblonged and will not allow the bolts in that location to tighten down securely. Make sense?

So I am asking for ideas on how to fix this? I can afix steel or aluminum plates and screw into that or what do you suggest?

 

[Woodonglass]

Re: Motor Mounts for a 4.3L Merc

Ok now that makes sense. If you can spin the mounts 180? then drill the holes over size using a spade bit. The Coat the holes and a piece of wooden dowel with 10 minute epoxy from Lowe's and insert into the holes. In 20 mins you can spin the mount back in place and screw em down. That's how I'd do it.

 

[jasonbrodsky]

Re: Motor Mounts for a 4.3L Merc

Thank you. That makes total sense.

 

[jasonbrodsky]

Re: Motor Mounts for a 4.3L Merc

I bought a piece of 5/8" dowl, sound good?

 

[Woodonglass]

Re: Motor Mounts for a 4.3L Merc

Prolly but I was thinking more like 3/4" or 1".

 

[jasonbrodsky]

Re: Motor Mounts for a 4.3L Merc

Okay.. I am screwed I think.... Went to drill holes for dowls and my worst my nightmare...

The wood in the engine area is totally soaked and rotted.

How far should I demo the deck to fix. Yes I found rotting on the stringer next to fuel tank as well.

 

[jasonbrodsky]

Re: Motor Mounts for a 4.3L Merc


OK. So I went to drill holes and found soaking wet wood. Opened more of the back deck, more wet wood. So I have to replace deck. How can I test transom?

 

[Woodonglass]

Re: Motor Mounts for a 4.3L Merc

Drill into the transom in various places about 1" deep and see what kind of shavings you get. I suspect it will be soaked and rotting as well. Sorry to say but I'd bet you've got a full gut job in your future.

 

[jasonbrodsky]

Re: Motor Mounts for a 4.3L Merc

Stringers and cleats seem easy. How is the transom replaced?

I did acouple places around the top of transom and the shavings were dry. I need to drill down towards bottom still.