Logo

Merctrans II Transmission Alignment

dmarcy

New member
I own a 1978 Hawaiian Day Cruiser with a Mercruiser 330 (Chevy 454) and Merctrans II Transmission (Serial #: 0012933 & Model #: MCM-D). The engine froze up in the winter and cracked the original block … So I rebuilt a Chevy engine (90’s model) to be put back into the boat. We had to do some engine mount work as the wood was rotted quite a bit. We currently have the new engine splined to the transmission, but since we had to work on the engine mounts and adjust the mounts I’m a little worried that everything is not aligned anymore. I know with the alpha/bravo outdrives it is critical to get the alignment tool and get everything aligned. But since we have an actual transmission between the outdrive I feel it may be a little different. We worked the engine and transmission for probably two hours by hand to make sure they went together without forcing anything. We wanted to make sure nothing was bent, tweaked, etc. Is there something I am missing? We didn’t remove the transmission from the back of the boat, so I feel when we put the outdrive back on those two components will be in line still. Is there anything I am missing to make sure the motor is aligned with the transmission? I’m not seeing any way to align the motor to the transmission except how I have done it. Please, any help would be greatly appreciated!
 
Not sure what you mean by jackshaft, but the engine splines to the transmission. The Mercruiser 330 TRS outdrive splines into the other end of the transmission with a shaft with two U-joints ( maybe this is what you mean by jack shaft?). Does this help? Or am I misunderstanding your question.

I didn’t mess with the transmission, only worked on the engine. So my thought is that the transmission and outdrive are still aligned even if I had to adjust the engine mounts a little.
 
Yes, that's a jackshaft....and the u-joints on each end will accommodate minor misalignments....

does the setup have a bearing on either end of the jackshaft??
 
Unfortunately, the manuals I have available don't include the TRS drives......I do have an older alpha manual that describes the alignment procedure when a jackshaft is involved.....I'm pretty sure what you need is manual #5....If you are on good terms with a local dealer, they may be willing to 'share' that data...

the mounts for the engine should have vertical studs with nuts above and below the trunnions....that's the hardware involved for a vertical adjustment.
 
I have a manual on the alpha drives as well. It makes since to me why those need to be aligned because the jackshaft literally splines right into the back of the engine... Just not sure how aligned mine needs to be because of the transmission between the engine and outdrive.

i will check around for a manual though. I’ve been told that there isn’t much on the TRS drives as far as manuals go.

i know how to align it, I’m just wondering if there is a way to “eyeball” it or get it close enough so parts aren’t rubbing in the wrong way.

thanks for your help!
 
Back
Top