1972 Mercruiser 3.0L How to align engine / gimbal bearing when the lower unit will not install

1972 Glastron with mercruiser 3.0L 140hp. I had changed motor mounts and could not get the lower unit back on. Even after using my gimbal bearing alignment tool, and adjusting the height of the engine, I could not get the lower unit go go the last 3/4" of an inch and install.

Solved the issue by installing the gimbal bearing disk on the tool, then inserting and heaving the tool: Up, Down, Left, Right. As I did this I could insert the tool farther until finally it went in all the way.

After recording the video, I installed the lower unit, it went on perfectly, it just slid right in.

To use the alignment tool: Put grease on the end of the tool, insert as far as you can, pull straight out, read the indexing left by the engine coupler in the grease.

Marks on top: Front of engine is too high.
Marks on bottom: Front of engine is too low.

Keep adjusting, and testing.

Again the final step is to heave the tool up, down, left, right and get both the gimbal bearing and engine coupler perfectly aligned.

8/7/2022 Had a problem with a 1970 mercruiser 120.
We could not get the alignment tool to go in with one finger even after trying this trick.
The fix was to use a crane to make large adjustments to the front of the engine.

-andy

[ZachsGarage]

Great video! I don't think I showed it in my videos but that heaving technique did the trick for me too!

[zerosource]

I was having issues getting my outdrive back in. I was searching for a video explaining how to adjust the rear mount. Thank you for showing to shake the alignment tool!! That's all it took and the outdrive slid back in!!

[Willy_On_Wheels]

Thank you so much for this!!! Been fighting mine for DAYS lol.

[jap]

Thank you Andy,  
this is the only video that addresses the alignment issues my son and I were experiencing. He struggled for a couple of days with it sliding in to within about an inch and a half and was forced to give up. When I came back home I searched YouTube and found your video. 30 minutes later it was in position.Wonderful! There is a lot of good videos out there but always the lower unit just slides easily in and makes you feel totally inadequate. Not any more!! John.

[airplanefred]

Nice video! Thanks for the tip on reading the indexing. Wish my alignment tool had come with the gimbal installation adapter.

[franciscotrujillo]

Si no esta bien alineado puede provocar vibraciones y un mal rendimiento del motor?

[stevengerhardt]

I've been scouring the internet for information on how to get this boat back together I watched every video I can imagine. I will try you're trick but I have a question. I to removed my motor because my wood was rotten. Is there any possibility that there's a left and right misalignment. The two bolts in the back seem to be were they are supposed to be. And I understand the motor mount up and down in the front. This thing is just extremely aggravating than any tips that you can give will be greatly appreciated. Thanks in advance.

[kubaSWAT]

Dear cna You please measure install ring for me please? Jakub