Engine swap.?.?

[69_norseman]

Hello everyone. I just joined the group today. I recently acuired a 1969 Crestliner Norseman powered by a merc 120hp i/o. Head gasket is currently bad according to previous owner.

However. As a back up plan and I discover there is a major issue and I need to do a repower, I would like to obviously up the power a bit. Now with that being said I know with a 4cyl hull there is only a mounting location at the front of the engine as with a 6 or 8cyl there are 1 on each side as well.

. Ultimately I would like to know if I can swap out my 120hp mercruiser with a 165hp mercruiser? Is it mechanically possible with the out-drive that is currently mated with the 120hp engine? Or will I need a complete set up for a 165hp engine? I am mechanically inclined and able to do modifications if need be.
I am asking this assuming someone has came across this idea or has done it.? I am new to forums and how to use them. I hope I put this in the roght place.

thanks in advance

 

[Scott Danforth]

get a complete setup from carb to prop, or find a 3.0 to bolt in where your 2.5 is. However I would find a 1992 or newer 3.0 to get the Alpha 1, gen 2 drive and one-piece rear main seal.

 

[Bondo]

Now with that being said I know with a 4cyl hull there is only a mounting location at the front of the engine as with a 6 or 8cyl there are 1 on each side as well.

. Ultimately I would like to know if I can swap out my 120hp mercruiser with a 165hp mercruiser? Is it mechanically possible with the out-drive that is currently mated with the 120hp engine? Or will I need a complete set up for a 165hp engine? I am mechanically inclined and able to do modifications if need be.
I am asking this assuming someone has came across this idea or has done it.?

Ayuh,.... Welcome Aboard,...... If ya wanta put in any motor, other than another 2.5l or 3.0l, you'll need to build new motor mounts,....
The I-6 is much longer, 'n of course any of the V-motors need side mounts,....

You'll also need a drive geared for whatever motor ya wanta use, or regear the drive ya got, which isn't cost effective,....

 

[kenny nunez]

The easiest, cheapest and most bang for the buck would be a new 3.0 marine engine. Slam dunk it in the boat and have fun. Trying to locate a in line 6 that is still good is a real crap shoot. Have the drive serviced with a new pump kit.
Other than the manifold all of the rest of the running gear on the 2.5 will swap over to the 3.0.

 

[thumpar]

If your drive is OK I would get a 3.0 and drop it in.