motor mount troubles

I am in the process of putting a 140hp mercruiser into a '69 ski boat, and can't get the splines to line up with the allignment tool. It seems as though the motor is sitting too high on the rear mounts. The mounts in the rear of the motor seem in good shape, and the fiber washers, and double wound lock washers were installed propperly. At best I can adjust the front mount so the tool is a tight fit, and when I pull it out and sight up the splines on the inside, the splines are too high toward the front of the motor. The only conclusion I can make is that the rear of the motor is too high, but I can't imagine worn mounts in the rear of a motor holding it too high. Anyone have some sage advice? Any help on this would be greatly appreciated.

Re: motor mount troubles

You can't adjust the front mount anymore ? No shims under the rear mount ?

The drive didn't drop did it ? Due to a rotten transom ?

Re: motor mount troubles

1. Is this the same engine and front mount that came out of the boat?
2. Is it a new coupler?
3. Is the transom rotten?

Re: motor mount troubles

the transom rot is an interesting idea, but the rear of the motor seems to be too high. Could transom rot cause this? Maybe from swelling? I pulled out a bad 120hp mercruiser 4cyl, and am in the process of replacing it with a 140hp one. The rear mounts of the original looked pretty bad, but the ones on the replacement motor seemed to be in good shape.

Re: motor mount troubles

If the rear of the motor seems too high, It's because the front of the motor is too low. Because your engine coupler sticks out past the rear motor mounts, there is a pivot point involved. Keep in mind, your motor doesn't sit level in a boat. It has to be square to the transome. Therefore your motor will sit high in the front equal to how many degree's your transome is angled back off the keel.

Re: motor mount troubles

Thank you for your input. my problem is that when the front mount reaches the point where the alignment tool begins to slide into the splines the front of the engine is too high. Neither raising nor lowering the front mount improves the alignment. When it is as good as I can get it, and the tool can access the splines, removing the tool, and sighting up the splines shows that the front of the motor is too high, in other words since the rear mounts are the pivot point, the only way to get the opening of the splines down to the center of the gimbal bearing, is to raise the upper mount too high. I don't understand how the rear mounts could be too high, considering it is nearly metal to metal with only the double wound washer, and fiber washer between the bell housing, and the engine block.??????? I am at a loss about what to do.

Re: motor mount troubles

Mike Beals said:

My problem is that when the front mount reaches the point where the alignment tool begins to slide into the splines the front of the engine is too high.

Click to expand...

Sounds like the gimble bearing needs to be adjusted/aligned. With the alignment tool out of the coupler but still engaged in the gimble bearing, bump the alignment tool's handle downward a touch which will shift the gimble bearing inside the carrier,,, moving the coupler end of the tool upward. Now you will (probably) need to lower the front engine mount a bit.

It's a balancing act, you not only have to adjust the engine/coupler angle with the front engine mount, but you also have to align the gimble bearing's angle,,, they both have to match each other and are both adjustable.

Go up to the "Adults Only" section and download the manual for your engine/drive, it will have all the details on how to properly align the engine.

Re: motor mount troubles

Very interesting you should say that. It is exactly what I was thinking about last night after posting, but my extreme inexperiance still had me second guessing myself. I have the good fortune to have the boat in the shop of a friend of mine who is a master mechanic, and access to a very kind marine master mechanic who loaned me the propper alignment tool, so with your helpfull words, it seems as though I may actually be able to get my project completed. Many thanks. Mike B