I/O Motor Mounts

[OkieWolf]

I have an '86 4 Winns 170. A couple of weeks ago I was on the lake and it kept wanting to turn on it's side at full or almost full throttle plus the bildge kept filling with water. When I got it back home I started looking for the problem. I found that all three lag bolts on the left (if in the boat and looking at the engine) front motor mount were out. They weren't gone, just unscrewed. The engine has four such mounting points. Apparently under the fiberglass these are built up wood to form about a 6"x6" "block" under each mount. Evidently water got under the fiberglass on that one block and enough of the wood is rotted to allow the lag bolts to come out. I tried to fix it by using contact cement, lag shields, and new lag bolts. I took it out Saturday and left the cover off so I could watch it. I went about a mile and it readily pulled the lags up again.

So, now I plan to take a Dremel and cut the fiberglass away from the mounting block to see how much damage there really is. Hopefully the bottom half will be alright and I can just scab on to it with new wood then re-fiberglass back over it. I don't want to pull the engine if I can keep from it. So, I have a couple of questions.

The leaking bildge only leaks when the lags aren't attached on the one motor mount. When this happens and the engine torques how is the outdrive boot leaking ? Is it pulling away from the transom a little allowing it to leak ?

If I leave the engine in the boat what is the best and easiest way to lift it enough to get some clearance (I'm sure I'll have to unscrew the right front mount also to raise the front of the engine) ?

Am I going to tear up anything else by leaving the engine in the boat and raising the front of it 3 or 4 inches ?

Any and all advice is welcomed and appreciated!!

 

[ErieRon]

Re: I/O Motor Mounts

Not a Tech., but just some advice.

I have a 23' 1984 Imperial with a 470 Merc. I just spun the splines on my engine coupler. Upon researching to find the proper fix I've learned a lot. Turns out that my lag bolts are all loose too. I too had a hard list to port the last two times I was out. I now suspect that the misalignment caused by the loose lag bolts is what took out my coupler splines. The stringer that my lag bolts thread into is completely rotten...hollow to a tap. At this point I don't think there is any way around removing the engine, replacing the stringer, coupler, and doing everything else that can't be done with this engine in (i.e. lower shift cable, trim sender/limit switch, front water seals).

If I were you, if you haven't already, I would remove the drive and check out the coupler splines. If they're compromised you will have to pull the motor anyway.

Also, the stringer repair really should be done properly or you'll be doing it again shortly.

Sorry for the reality, and it's just my opinion.

 

[OkieWolf]

Re: I/O Motor Mounts

Yes, I know. And I agree that it would be so much easier with the engine out of the way plus I could check the other mounts. And you're right, the others probably aren't far behind this one in needing to be replaced.

But I don't want to pull the engine....

 

[Fishermark]

Re: I/O Motor Mounts

Better to know the bad news up front... not only will you have to pull the engine, but the outdrive too. The fact that it is flexing and leaking means the transom is shot as well. That means the entire transom assembly needs to come off and the transom rebuilt as well. At this point you need to decide if the boat is worth the time and money. It may be of course, but only you can decide. Simply patching the bad mount will not do much good.

 

[ErieRon]

Re: I/O Motor Mounts

I don't want to pull mine either, but nothing else makes sense in my situation. I've read the manual over and over and it really isn't that difficult to disconnect everything. Now, fixing everything is a different story

I've resigned myself to the fact that boating is over for me this season, and I'm going to take the fall/winter and do it right.

Good luck.

 

[Fishermark]

Re: I/O Motor Mounts

I've read the manual over and over and it really isn't that difficult to disconnect everything. Now, fixing everything is a different story

You hit the nail on the head. Pulling the engine is nothing to fear. Fixing everything else is another story.

 

[OkieWolf]

Re: I/O Motor Mounts

But there is absolutely no evidence outside or inside the engine compartment of the transom being bad. I've looked high and low trying to see if I could see anything leaking through the transom and have found nothing. And, Saturday everything was fine until the lags pulled loose. It wasn't leaking at all before the lags pulled up but started after they came loose.

The engine torques toward the port side pretty hard at full throttle when the starboard mount lags are loose (obviously) and appears to be only leaking in one spot on the port side so couldn't it be twisting the boot somehow or causing it to gap a little. The water isn't gushing in but enough to eventually kick the bildge pump on.

 

[Fishermark]

Re: I/O Motor Mounts

What engine and drive do you have?

 

[OkieWolf]

Re: I/O Motor Mounts

It's a 4.3L 6 cyclinder, OMC.

 

[ErieRon]

Re: I/O Motor Mounts

OkieWof;

I would be more concerned about your engine coupler at this point. Have you removed the drive yet?

Also, do you have the Mercruiser Service Manuals? You can download any of them here; http://forums.iboats.com/showthread.php?p=1693398#post1693398

I think your 470 is No. 3, and if you have an Alpha One I think it's No. 6...double check for yourself though.

I understand what you're saying about the water intrusion, and I don't know much about the transom assembly, but I do know that it is supposed to be water tight. I'm not convinced that you would get water in through your bellows under your circumstances...more likely the transom seal.

 

[Fishermark]

Re: I/O Motor Mounts

ErieRon - he doesn't have a Mercruiser, he has an OMC. I am not familar enough with OMC to suggest a solution... but I would be surprised if your transom is not an issue. I hope it turns out to be okay... but maybe someone with more OMC experience can chime in here.

 

[OkieWolf]

Re: I/O Motor Mounts

But what really pisses me off is that this engine had been rebuilt when I bought it and is awesome and runs perfect, starts every time, and have never had any problems with it.

 

[ErieRon]

Re: I/O Motor Mounts

ErieRon - he doesn't have a Mercruiser, he has an OMC. I am not familar enough with OMC to suggest a solution... but I would be surprised if your transom is not an issue. I hope it turns out to be okay... but maybe someone with more OMC experience can chime in here.

Sorry guys, from his first post I ***-u-me-d he had a Merc 170 (former 470). The Merc. manuals probably won't be a big help then...

 

[OkieWolf]

Re: I/O Motor Mounts

What do you guys think about this thread and filling the empty fiberglass mounting shell with wood and fiberglass and/or seacasting (whatever that is) ?

 

[fishrdan]

Re: I/O Motor Mounts

I tried to fix it by using contact cement, lag shields, and new lag bolts.

Replacing the wood mounts would be the best idea as they are most likely rotted. You could try a bigger lag bolt, but that could strip again if the wood is rotted.

As for your idea of using lag shields, it worked on my Mercruiser 140HP for years, but I did it different. I oversized drilled the holes to where the lag shield would slip in, then drilled to the sides at an angle in a few spots to widen the bottom of the hole a bit. Mixed up a healthy batch of JB weld, coated the inside of the hole and filled it about 1/3 full, coated the outside of the lag shield, pushed the las shield into place, melted wax onto the lag bolt to coat it with a thin film and then ran the lag bolt into the lag shield. This epoxied the metal lag shield into the wood, but allowed removal of the lag bolt.

Worked great for about 5-10 years until I discovered Iboats, the problems with rotten wood in old boats and that my boat needed to be completely rebuilt. It was a Band-Aid fix for a broken leg, but worked.

 

[Lou C]

Re: I/O Motor Mounts

I didn't realise that FW put the 4.3 in the 170...seems like it'd be a tight fit...to remove the drive you need to put the shift control in neutral...support the drive under the skeg (maybe get someone to help you with this....I built a stand for mine)...remove the nuts on the rod that holds the trim rams...tap the rod through the drive housing and let the rams drop down...remove the 6 nuts that hold the drive to the pivot housing...and then pull the drive straight back...support the driveshaft as it comes out so it doesn't knick up the surface of the splines...then deal with pulling the engine...or at least lift it up enough to assess the damage to the mounts...I wouldn't try this with the drive on because you might bind up the driveshaft in the coupler...I'd still want to check for softness around the opening in the transom for the drive mounting...
for the offical OMC removal/replacement steps see
www.crowleymarine.com
look in product support...OMC Cobra drives...it's all there with factory pix...

 

[OkieWolf]

Re: I/O Motor Mounts

Yeah the contact cement worked about as good as Elmer's glue....
It ripped the lags and lag shields both out this time. I can't put bigger lags in it because the holes in the metal engine mount are a set size. I suppose I could ream those out but I don't really want to do that.
And yes, I realize this would just be a temporary fix. But I'm thinking about whether to pull the engine. I bought the boat a few years ago from a marina on the lake by where I live and we know each other pretty good. They aren't open today but I may go over there tomorrow and see what they would charge me to do it. I'm not confident that I have enough "boat mechanic" in me to pull the engine and outdrive and then get it all back together again.

 

[OkieWolf]

Re: I/O Motor Mounts

I didn't realise that FW put the 4.3 in the 170...seems like it'd be a tight fit...

Like I said earlier, this engine was rebuilt so I'm not 100% sure that it's factory. And yes, it's snug.

 

[OkieWolf]

Re: I/O Motor Mounts

for the offical OMC removal/replacement steps see
www.crowleymarine.com
look in product support...OMC Cobra drives...it's all there with factory pix...

The outdrive on mine looks nothing like what they show. My outdrive has no pivot rods like that. Mine has two huge gears (one on either side of the outdrive). So what's the deal ? Is mine some kind of funky system ? It says OMC plain as day on the outdrive.

 

[Fishermark]

Re: I/O Motor Mounts

It doesn't look like this does it? With a big rubber boot around the outdrive. (I assume it does not, but I have to ask. )