engine swap 3.0L OMC to a 4.3L OMC

[agwa2111]

I have a 1988 Bayliner Capri 2150 with a 3.0L OMC. I just bought it from a guy. It has a locked up oil pump. My thought is that sence i have to pull the motor to change oil pump might as well upgrade. in my opinon the 3.0L is under sized for this boat. Can i put a 4.3L in it. i will probably have to glass in 2 new motor mounts , and change the gears in the upper unit. Im i on the right track or am i missing something?

 

[Don S]

Re: engine swap 3.0L OMC to a 4.3L OMC

Have a look at this post. You will have the same problems he has, only you also have an outdrive that has to be replaced. The 3.0L outdrives were ligher built and the wrong gear ratio for a 4.3.

http://forums.iboats.com/showthread.php?t=370211

 

[agwa2111]

Re: engine swap 3.0L OMC to a 4.3L OMC

thx Don for the response. I found a complete marine 4.3L OMC out of same year Chaperal with cabs, manifolds and everything for $600 and also has the complete upper unit for $600. Isn't thelower unit the same on both 3.0 and 4.3? or still not worth my time?

 

[Don S]

Re: engine swap 3.0L OMC to a 4.3L OMC

No, the lower is completely different for the 3.0L. It's much smaller.

 

[agwa2111]

Re: engine swap 3.0L OMC to a 4.3L OMC

ok sence the engine swap is out of the question. What can i do to the engine to get the best hole shot and good midrange out of my 3.0? I'm going to bore it 3 over and put flat top pistons in it. Is there a cam upgrade or can i get a bigger cam made for the 3.0? work the head and let the valve breath a little? or am i stuck with the stock 3.0? i'm 250lbs and like to ski but don't want to drink alot of water. thx again

 

[Bondo]

Re: engine swap 3.0L OMC to a 4.3L OMC

Ayuh,... Put a smaller prop on it,+ be happy, til you up-grade to a more powerful boat...

 

[jtybt]

Re: engine swap 3.0L OMC to a 4.3L OMC

I did that swap for a friend last year. Luckly, my friend got he 4.3 and drive...which it needed.

IT WAS A 100% STRAIGHT SWAP...as long as the drive year/transom cut-out is the same. The engine dropped straight in. NO ALTERATIONS!!!!!