motor mount bolts loose

[Adam10705]

I have a 92 supra impulse that i just got, the floor is really solid with no soft spots in it. i was doing some mainteness on the boat and noticed that one of my motor mount bolts was missing. So i grabbed a wrench and checked all the others and a couple were still tight but the others would not tighten up at all. Im in a bind now about what i can do because im not sure what the motor is mounted to and what im going to have to do to fix it, i know theres alot of guys on here that know these boats inside and out and im looking would appriciate any help.

[Ptownkid]

Man, i don't want to be the one to say this...and I hope I'm wrong, but it sounds like the stringers that your motor is mounted to are rotten/rotting.

As for what to do...try searching "stringers" on this site and you should get a ton of hits.

Cheers

[csuggs]

On a '92 I'm not sure if you have wood or fiberglass stringers. I'm sure that someone on here will know. Either way it needs to be fixed before the season or you could do some real damage to your boat - if the motor moves you could even sink it. If the stringers are wood you need to replace them which is a job. If they are glass, then I would think the problem could be repaired by removing the motor and using some sort of marine fiberglass repair epoxy or something to fill the holes so that you could re-drill them. Even the worst case isn't so bad considering that many of us on this forum have already been through it . . .
Good luck and let us know how it goes.

[beast 496]

Here is what I would recommend first, Remove the smaller 3/8" lag bolts and try replacing with 1/2" SST lag bolts. If they do tighten up, pull back out and mix up some resin to place into the bolt hole, and then reinstall the 1/2" SST lag bolt Each mount should have two going vertically down and another two shorter going horizontally 16 bolts all together. If this works you could get another season easily out of the boat. Good luck Al

[sybrmike]

I'd drill some test holes to determine for sure if you're wood or composite so you know if you need to bandaid a temp fix in rotten wood, or feel good about a permanent repair in composite (lucky you?).

[csuggs]

Here is what I would recommend first, Remove the smaller 3/8" lag bolts and try replacing with 1/2" SST lag bolts. If they do tighten up, pull back out and mix up some resin to place into the bolt hole, and then reinstall the 1/2" SST lag bolt Each mount should have two going vertically down and another two shorter going horizontally 16 bolts all together. If this works you could get another season easily out of the boat. Good luck Al

I agree with Al. But you might have to drill out the holes on the mounts themselves to accomodate the bigger lag. Having just re-installed my motor over the weekend, I'm pretty sure I would not be able to just put a 1/2" lag in place of the 3/8" until I drill out the hole in the mount to 9/16". Do you know if the stringers are wood or glass? Clint

[Adam10705]

Im hoping they are glass but not sure im at work now and when i get home ill check, where is a good spot to drill test holes and how big of a hole?

[cadunkle]

I did similar to Al on my last boat, an I/O that had soft stringers in the motor mount area. There were only 4 bolts holding those mounts in, 2 straight down on each side. It wasn't worth it do do stringers on that boat (to me anyhow) and I was looking for an inboard anyway. I got some longer lag bolts and some concrete anchors. I put some epoxy in the holes, pounded a concrete anchor into the holes, then filled holes to top with epoxy and installed longer lag bolts through the motor mounts.

After that I didn't see any signs of the engine moving after another season on the water. I figure it's good for a couple years before it really needs a stringer job but that's not my problem since the boat is long gone. So you can probably do similar to get through the season and plan on doing stirngers over next winter.

[csuggs]

Im hoping they are glass but not sure im at work now and when i get home ill check, where is a good spot to drill test holes and how big of a hole?

I'm sure someone here knows - all I know is that is about the time Supra went to fiberglass. Regardless, Al's solution should work. I would not drill test holes, but instead remove bolts that are already there and look for either wood or plastic debris on the threads.

[Adam10705]

whats a good epoxy to use if i am going to use longer lags?

[jet]

If I recall on the 92's..curved winsheild=fiberglass floor, squared off windsheild=wood. But you still have to test because I have heard of a few curved windsheilds with wood due to the leftovers and change made that year.

[Adam10705]

square windshield, I would love to get 2 seasons out of it before upgrading i know band aid fixes arnt the best but if i could get it to were im comfortable the motor wont shift on me i would be extreamly happy, i would hate to think I have to do all new stringers this close to the season being here

[Okie Boarder]

You can look into the various products offered by Rot Doctor if you go the repair route. Those might be better options than just epoxy.

www.rotdoctor.com

[mapleleaf]

the jury has always come back saying that during those years '91-'92 the curved windshield indicated fiberglass stringer's , but didn't make it a sure thing.
Likewise a square windshield might indicate wood stringer's, but didn't always.....
Hope your research find's it's answer!

[Ptownkid]

I checked with Jim again today. In 92 if it has a squared windshield it is wood. During that year they made 3 barebones boats that were wood with square windshields one was the spirit(sunsport), esprit (conbrio), and the other is the Impulse (comp).


I'm pretty sure this is right...

[Adam10705]

If i use the rot doctor to fill the holes do i only need to use the CPES sealer? Or do i also have to get the layup resin and the fill it?

[Okie Boarder]

You might call them to ask. Maybe some others have some experience. I've heard that an approach is to use the CPES, then do some sort of filler and epoxy to finish it off. But, don't rely on the little bit I know about it. They have good tech support and they are the experts.

[sybrmike]

Just my $.02 - but if I were going to try and bandaid engine mount holes in questionable wooden stringers...

Pull the engine/trans, use a 2-3" dia deep hole saw bit to drill the holes out so that the side and top holes meet, use a chisel/screw driver to dig out any remaining soft wood behind the holes in the fiberglass (if nothing but mush comes out - all bets are off), put some heat/fans on it for a week to dry it out, soak the bajeesus out of it in several coats of CPES, tape the side holes & fill from the top holes with a thick putty mixture of epoxy resin and chopped fiberglass so that you have solid cores (may take a few passes to fill it up good), rough sand the area surrounding the holes and lay a ~8" wide layer of heavy cloth over each mount area, redrill new holes.

It all really depends on just how bad the wood is behind the glass & how much risk you're willing to take. Good luck (fingers crossed for you...)!

[Adam10705]

thanks mike that sounds like a great plan, going on vacation here in the next couple days when i get back i have to get bustin on the boat if i want to take it out as soon as the weather turns, ill take pics and keep you guys posted and im still open for ideas from people.

[wotan2525]

The Rot DR will never setup unless the wood is DRY DRY DRY. Without seeing your situation, I can't tell you if you can band-aid it or not. All I can tell you is that I tried several different things (including: heat, fans, demumidifers, rot dr, fiberglass, lag bolts and gorilla glue) and my boat ended up giving up the mounts, the engine shifted, wore through the shaft log and sank in 2 feet of water. It was bad. And my date was pissed at me. Good luck!

[sybrmike]

Dang Wot - most guys just find a way to, ahem, run out of gas at the end of a dark road. Too many stories like yours (glad it was only 2 ft deep) to recommend bandaiding motor mounts, mine was just a suggestion if someone were willing to risk it. Heck, my bolts were tight & I still tore her apart rather than risk it.

Agreed, wet wood can take forever, if ever, to dry out. Hopefully Adam can find some strong dry wood & make a good decision...

[wotan2525]

Hah! If there was insurance on it at the time it would have been headed for deep water.... Not paddling like crazy to get to shore! The hardest part was finding enough pumps/batteries to get it out and then pulling it the 8 miles back to the launch.