Front motor mount 1984 120/2.5L Mercruiser

[daydreamer1252]

Posted this question on the rebuilding forum and didn't get the ideas I was hoping for. Maybe will get another look at the problem here.

In the process of transom replacement. Found the front motor mount screwed in to a few layers of f'glass only. All wood below it is gone. Will have to replace this. Now the question.

How does one get the mount back in the same/correct place?? There are really no hard points or datum line from which to measure. Everything is pretty much in a state of limbo. On the other forum asked about making a template or other ideas and basically got "...it don't matter..." and this seems wrong.

Any ideas here? How critical is the placement? +/- .125 or .250 more? Less? Where can one find the installation drawings? Is this the proper way to go about it and "get it right"? Or does it really not matter??

As always, any and all help is appreciated.

Thanks

 

[Don S]

Re: Front motor mount 1984 120/2.5L Mercruiser

You have to remove the outdrive and use an alignment bar to get the alignment just right or you will destroy your coupler. If the coupler goes out, you have to pull the engine to replace it.
Sure hope you haven't left the drive on and been straining the coupler with the engine lifted way up (or down)

 

[daydreamer1252]

Re: Front motor mount 1984 120/2.5L Mercruiser

Don S. Thanks for the reply,

Am still in the process of putting the transom in and I have to completely remove the forward motor mount and replace all material beneath it. This will require me to position the front motor mount anew (from scratch). I have a completely bare hull at this point, stringers and bare floor. I have an alignment tool and that will be helpful when installing the outdrive. What I am concerned with is getting the engine back in the boat in the correct location so that I can line up the outdrive correctly. At this point the front of the motor will be "floating" until I can determine the correct location of the front motor mount.

Thanks again

 

[45Auto]

Re: Front motor mount 1984 120/2.5L Mercruiser

The rear motor mounts (on the transom) will take care of the side-to-side alignment. Don't drill the holes for the lag bolts on the front mount until AFTER you've bolted the engine to the transom. If the fiberglass the original front mount was bolted to is still there, measure the height from some reference point so you can duplicate it. The height isn't super critical since you have a lot of height adjustment on the front bolt that goes to the engine. If the original hull brace or stringer the mount was bolted to is already gone, then bolt the rear mounts on, set the adjustment for the front mount in the middle, and use a jack or hoist to raise or lower the front of the engine till the alignment tool is happy. Mark the height of the bottom of the motor mount and make that the height of your new stringer to attach the mount to.

 

[daydreamer1252]

Re: Front motor mount 1984 120/2.5L Mercruiser

Thanks 45Auto,

I had hoped and thought that the rear mounts would be sufficient to locate the engine. I was not comfortable enough, as I had not done this before, to trust my feelings. Glad to get an opinion from someone who has been there before. I should be able to get the new wood/glass for the front mount w/in +/- 1/4" very easy and probably +/- 1/8" and either should put me in the ball park.

Now back to the chain saw and get the old mount out so I can get the f/glassing done and get to the water.

A boat that doesn't float is a very unattractive lawn ornament....