Mixing Mercruiser 120 ( 1971 ) with Alpha Gen II ( 2000 4.3L )

[matt167]

I was cleaning up my '71 SC Offshore V18 to sell when I decided not to. I bought it with the gimball all apart and the nails/ pins are gone as well as a couple shift linkage parts and it's kind of corroded. The guy who I bought it from was restoring it when he found an Islander. He did redo the engine and transom and the interior is done as well, which is why I bought it.

I do have a 2000 Smoker Craft parts boat. It was a 4.3L Merc. Outdrive is gone, but transom plate back to the locked up 4.3L is there ( no carb or manifolds ). Can I put the 1971 bobtail 2.5L in front of the Gen II transom plate and have it work? The 2.5L has a full new manifold. The 2000 still has the power steering but is missing trim pump and rams

 

[Scott Danforth]

You will need to simply swap the 2.5 in where the 4.3 was and use the A1G2 flywheel housing

 

[matt167]

You will need to simply swap the 2.5 in where the 4.3 was and use the A1G2 flywheel housing

will the Gen 1 shifter and trim buttons work? It uses an old side mount Mercontrol

 

[Bondo]

will the Gen 1 shifter and trim buttons work? It uses an old side mount Mercontrol

Ayuh,..... It shouldn't matter,....

 

[matt167]

Is it really worth it to swap to a gen 2 or should I get a newer gen 1 transom plate? Being I have a good gen 1 leg. I’ve got the approval from the other half on this so I might have a decent budget

 

[dubs283]

Is it really worth it to swap to a gen 2 or should I get a newer gen 1 transom plate?

This is the route I'd go. Plenty of alpha one/mc1 transom assys available on ebay and craigs in the right market.

Would definitely inspect carefully before purchase and expect to replace all bellows, senders, etc....

 

[matt167]

This is the route I'd go. Plenty of alpha one/mc1 transom assys available on ebay and craigs in the right market.

Would definitely inspect carefully before purchase and expect to replace all bellows, senders, etc....

The one I have uses the pins that are held with pins and nails.! I have new pins and nails but the nails are broke off inside. I’d like to have trim senders too

 

[dubs283]

There are mc1 transom assys that use threaded pins for the bellhousing with most recent available senders.

Look for late 70's early 80's mc1 assys

 

[matt167]

There are mc1 transom assys that use threaded pins for the bellhousing with most recent available senders.

Look for late 70's early 80's mc1 assys

I knew that but didn’t know what the serial or year brake was for it. Or if the driveshaft difference would matter

 

[dubs283]

Splined shaft length should not matter as long as you retain the inner transom plate which will mate with any mc1 gimbal housing

 

[matt167]

Splined shaft length should not matter as long as you retain the inner transom plate which will mate with any mc1 gimbal housing

That makes sense now

 

[matt167]

Would an 86 boat with 2.5 merc be a good candidate?