Merc 4.3 Alignment

[300sflyer]

Checking the engine alignment on a 2000 Merc 4.3 with an Alpha gen2 drive, in an 18 bowrider. The boat is in prestine condition, with what appears to be very low hours. [no meter] My alignment tool will only go into the coupler about 1/3 of the way, and it gets stuck. Tried rotating the engine 180, and hitting the alignment bar with a rubber mallet, but neither made any difference. Pulling it out, it shows grease marks only on the top. I tried to adjust the front of the engine down, however both engine mounts are already as low as they will go. The engine does not look as though it has ever been out before, but cannot be sure.

Any suggestions? The coupler splines look to be in good shape, but I can't imagine it will stay that way very long with the alignment so far out of wack.

 

[Don S]

Re: Merc 4.3 Alignment

Sounds like the front mounts were built too tall, or the transom cutout was mis-located.
Is all the proper hardware on the rear mounts?

 

[300sflyer]

Re: Merc 4.3 Alignment

Far as I can tell, everything on the rear mounts is as it should be. I will try loosening the rear mount bolts, and see what that does. Can I just add a washer or two under each side to raise it up a bit?

 

[Don S]

Re: Merc 4.3 Alignment

It's not so much loosening them, that does nothing. Is the double wound washer and fiber washer under both rear mounts and the inner transom plate.

Is this the first time the drive has been off a 2000 boat???????

 

[300sflyer]

Re: Merc 4.3 Alignment

I have no history on the boat Don. I was asked to pull the drive and check things over. All the bellows and the gimble bearing look new, so I assume this is not the first time the drive has been off. It appears as though an alignment was attempted, but could not be done properly, as they ran out of adjustment. Looking with a flashlight and mirror, the double wound washer and the fibre washer are there on both sides. I'm looking for the easiest possible fix to correct the alignment.

 

[300sflyer]

Re: Merc 4.3 Alignment

Anyone have a suggestion on how to fix this alignment problem? I'm thinking of lifting the back of the engine a bit, and adding a washer under each side to raise it up a bit. Would there be any issues with this?

 

[cedgo]

Re: Merc 4.3 Alignment

Hello! Interesting question. Had same problem, added washer to each side, snugged everything down, alignment tool slid like butter.
Everything in line, should be good to go.

 

[300sflyer]

Re: Merc 4.3 Alignment

I assume you used an additional flat washer on each side, and not a second double wound washer?

 

[Don S]

Re: Merc 4.3 Alignment

Yes, just a regular thickness flat washer, and I would put it under the double wound washer.
Merc used this method on the newer style rear mounts on some of the older engines, it just might work for you. You just want to raise it up a little bit, too thick a washer and it will be way off the other way.

 

[300sflyer]

Re: Merc 4.3 Alignment

A washer on each side did the trick. The Splines in the coupler are not running perfectly true, but it is pretty close.

Thanks for your help guys!