rear engine mount trouble (alignment)

[dixieboater165]

I have a 1987 Mercruiser 165 w/ a Alpha One drive, and I rebuilt the outdrive( new bearings/seals) and now I am trying to get it back on. I got it on most of the way then it stopped with about an inch left. I pulled it back out and took apart the drive shaft (could use a new spider anyway) to see if I could insert the shaft. I took the o-rings off and put the shaft in and it stops. I made sure the Gimbal bearing was seated properly and it didnt help. I concluded it had to be an engine alignment problem. I messed with the adjustment, but it didnt help. The engine is too high. I loosened all the mounts and raised it enough to take out the lock washers and fiber washers. I set it back down (without the bolts and washers) and the shaft went in further but not all the way. I cut the old fiber washers in half (heighth-wise) and put them in (w/o the lock washers and spacers amd bolts)The shaft slides in like a dream. Why would this be! I am ready to put it back together with half-height washers. I think this will work, but it will have to push the rubber bushings up a little so the engine can set on the washers. The bushings wont slide up any. Are they bonded to the ID of the engine mounts? Sorry for the long post, I just want to know how the engine could be too high and if my "rigging" will work.

 

[jeff13601]

Re: rear engine mount trouble (alignment)

The back mounts would not have moved. You do the adjustment from the front mount. Merc has an engine adjustment tool that you have to use. Unless you are lucky you are asking for trouble. You could have been having trouble because of a dirty coupler. Old grease can get pretty hard. Did you use a good amount of grease on the spline?

 

[dixieboater165]

Re: rear engine mount trouble (alignment)

The first thing I did when I suspected it was an alignment issue was run the front mounts up and down while having someone trying to insert the shaft to see if it got easier. It didnt help in any position. Yes I had plenty of Quicksilver mulit lube 2-4-C on the splines.

 

[jeff13601]

Re: rear engine mount trouble (alignment)

You really need to put the rear mounts back together and get an alignment tool. You might try having someone rock the crank back and forth after you get it aligned while you push in on the outdrive. If the engine is not adjusted properly you will soon be pulling the engine and replacing the coupler

 

[Don S]

Re: rear engine mount trouble (alignment)

You need the alignment bar to "Align" the coupler to the drive through the gimbal bearing. The rear mounts do go bad and allow the engine to drop. At that point you have to replace them. Then make sure the double lock washer and fiber washer are under the mounts when all together.<br />Bad rear mounts have destroyed a lot of couplers, so it's not uncommon at all.<br />Adjust the front mounts up and down till the alignment bar slides in and out of the coupler easily. Many times the gimbal bearing will get moved and have to be aligned with the alignment bar by tapping (NOT pounding) the bar in and tapping around the handle to center the gimbal bearing.<br />Easy to show, hard to explain.<br />Here are a couple of pictures that may help you see the process.<br /><br />

<br /><br />

 

[dixieboater165]

Re: rear engine mount trouble (alignment)

How is the alignement tool different than the shaft? Is it slightly smaller in diameter? Does it have markings? (I've got the shaft off the outdrive. My problem is that the engine is too high in the back. Not that it has sagged. The shaft goes in easily with the old fiber washers cut in half. (with the engine about 1/8" lower)

 

[jeff13601]

Re: rear engine mount trouble (alignment)

Dons pics make things so much easier to understand

 

[Don S]

Re: rear engine mount trouble (alignment)

The shaft goes in easily with the old fiber washers cut in half. (with the engine about 1/8" lower)

You are asking for trouble. your engine is probably way to low in front making the rear look to high. But if you don't have the rear mounts put together with the proper parts, then you are doomed to pullingt the engine and replacing $350 couplers frequently.

 

[dixieboater165]

Re: rear engine mount trouble (alignment)

Well, Ill put in some new fiber washers and lock washers tomorrow and raise the front of the engine while checking if the shaft will go in. I did this before, but maybe I didnt go high enough. I hope so. May need some more help tomorrow. Thanks.

 

[dixieboater165]

Re: rear engine mount trouble (alignment)

I put new full-size fiber washers in an adjusted up and down the full travel of the threaded rod. It just got harder. I do not know why, but the back of the engine is too high and adjusting it in the front does not lower it enough. I put the half-size fiber washers in and some single wound lockwashers instead of the double wound. I tightened it up and the shaft slides in, but with too much resistance. I had someone stand on top of the engine and it squished the rubber bushings down enough that the shaft slides in easy. I clamped the transom mount to the engine mount (which squished the bushings more) and it slides in even easier. The engine still needs to be lowered. This is what I am going to do. The fiber washers are the correct height, but the lock washer is pushing on the bushing, so that the lock washer is what is spacing the mounts apart, not the fiber washer. In order for it to be the correct height, the bushing inside the mount needs to slide up very slightly. It won't slide up. Is it bonded to the ID of the mount or is it just a tight fit? I know this goes against what everyone has said, but I see that adjusting it in the front does not solve it and that lowering the engine clearly does solve it. I dont know what else to do so I am going to try it and see if it vibrates. I just need to lower it a tiny bit more by letting the bushing slide up a little. Should it slide?

 

[garycinn]

Re: rear engine mount trouble (alignment)

Are you sure you are rotating the gimbal bearing with the alignment tool to "find" the coupler?

 

[dixieboater165]

Re: rear engine mount trouble (alignment)

If by "find" you mean letting the splines line up, then yes. I mean the shaft goes all the way in when the engine is lowered. So I must have "found" the coupler.

 

[gspig]

Re: rear engine mount trouble (alignment)

Dixie, get an alignment tool. I also thought that I could align with just a driveshaft. I couldn't get the driveshaft to seat properly and gave up and got a tool. I had to drop the front of the engine as low as it will go. I also found that once the tool slide easily that the driveshaft still wouldn't go well. I put the tool back into the couple and pushed the tool handle in a circle. The gimbal bearing can shift off plane which effectively causes the bearing opening to be smaller. Once I set the bearing in plane, the driveshaft slide easily and seated all the way to the yoke.<br /><br />Add: Got my tool from e-bay auction. If you get one from there, you will have to sand the paint off. He machined the bar to tolerance, but the paint thickness makes the bar too big.

 

[MATMAN29]

Re: rear engine mount trouble (alignment)

I just went through the same thing with my 98 merc.You need to move the gimble bearing around in its cage to find the right spot The bearing sits in a cage like an eyesocket you can move it up,down and side to side but it takes some pressure on the alignment tool to do it.I moved my front mounts up & down and even replaced my rear mounts and still couldnt get it aligned untill I moved the gimble bearing to the right spot.it takes time but it will be worth getting it right.couplers are expensive.Get your self a good alignment tool and insert it into the gimble bearing but not so it is in the coupler and move the bearing up or down or what ever way it needs to go. Good luck, Matt

 

[garycinn]

Re: rear engine mount trouble (alignment)

gspig and matman have it nailed.<br /><br />I got my alignment tool from mercstuff.com and was very pleased.

 

[rickf1985]

Re: rear engine mount trouble (alignment)

Gentlemen, I want to thank you profoundly. I was having the same problem as Dixie and I followed your advise about moving the gimbal. Now the tool slides in smooth as silk. Dixie, it does work believe me. <br />Rick

 

[MATMAN29]

Re: rear engine mount trouble (alignment)

glad I could help-its what this forum is all about

 

[Scaaty]

Re: rear engine mount trouble (alignment)

Dixie, what they are saying is you are moving the engine to fit the bearing, when you should be moving the bearing (the bearing needs to be moved UP in your case)...get the tool

 

[steve n carol]

Re: rear engine mount trouble (alignment)

Dixie...for a while I taught youz a Coon A$$,<br /><br />Now I see that you are from Georgia. <br />Have you worked on your transom any more than just the eyelet areas?<br /><br />Like, changing the area where the transom assembly mounts, thus changing the height of the outdrive?<br /><br />Also, when you removed the outdrive, how difficult was the process? did it just 'slip' out?<br /><br />The alignment tool is simple in design, (no moving parts, but alignment is critical! perhaps you might rent one at a local marine shop.<br /><br />Being 16 or 17, (now), I am sure that some of the techs at the shops would enjoy you being around, (a summer job). Keep up GOOD work and don't turn into a 'hack' mechanic....enjoy...sl

 

[dixieboater165]

Re: rear engine mount trouble (alignment)

I haven't done anything major to the transom other than the ski eyes. I did slightly tighten the bolts on the transom plate last year. That was my thought, that maybe when I tightened them down, the transom squished a little at the top, rotating the plate and gimbal bearing down. I did not get an alignment tool but I did find a socket that fit the ID of the bearing and put a long extension on it. Should have the same effect that the alignment bar would have when lining up the bearing. It did not help the shaft going in. I looked at the old bearing that I pulled and the inner race was cocked in the direction it needed to be. I think maybe that the transom plate has somehow shifted. The guy that had the boat before me had a part time mechanic work on it. I think he could just talk a good line and didn't have a clue. Theres no telling what he has done to that transom plate or anything else.