888 MerCruiser Motor ALignment On New Motor Mounts

[c384id70]

I have removed the transom, front motor mounts/stringers and gas tank bulkhead on my 1974 Reinell 25' Cabin Cruiser. The wood was totally rotten and after removal, I believe at least the motor mounts/stringers had already been replaced and it wasn't a pretty sight. I do not feel comfortable using what I took out for many measurements even though the gimbal shaft alignment must have been OK.

Is there an Email sight with the original specifications or anyone out there that can give me some help on this with tips or tricks that might help?

I have built new stringers, front motor mounts, front gas tank bulkhead and rear transom. The transom is in, the bulkhead, stringers and motor mounts are ready to go in. My mounts have plywood pads on the bottoms for weight distribution and to have more area to tab in the mounts. The stringers will go right behind the mounts towards the outside of the boat. The original fiberglass transom was used to cut the keyhole out so that should be spot on.

What I'm looking for is the distance between the MerCruiser rear motor mounts built into their inside transom mount and the MerCruiser front mounts that go on my wooden motor mount pads. How do you measure the height of the front mounts relevant to the rear mounts? Do you measure the diagonals between the rear and front mounts to make sure they are square?

This is old stuff but it is working great so I hope someone as old as me can remember the good old days.

 

[Don S]

Re: 888 MerCruiser Motor ALignment On New Motor Mounts

The only way you can get the dimensions you need is to install the gimbal housing and inner transom shield. Then install the engine, while still on the hoist, properly install the rear mounts. Then use the alignment bar to align the engine. Then set your front motor mounts down as low as they will go and Measure for your mounts. Then pull the engine back out and build your mounts and fiberglass as needed.
Then put the engine back in, center your mounts and do the alignment check again. If you need a spacer to keep the mounts centered on their thread, make one out of aluminum or plastic. Then lag it all down and do your final engine alignment.

 

[dollarten]

Re: 888 MerCruiser Motor ALignment On New Motor Mounts

Just a thought , If you still have the original outline where the transom plate was originally , this dimension will automatically determine where the engine will sit in the boat . The transom plate is bolted to transom and everything will line up except the front adjusting jacks . This is where you will have to suspend the engine in order to get the alignment bar in and go from there . If there is no original transom cutout , the only guideline is to mach everything up so the cavitation plate is level with the keel