3.0 omc engine mating to mercruiser outdrive

[jclark178]

Does anyone know if you can mate a 3.0 omc engine to a mercruiser outdrive, particulary in the bell housing drive shaft area. can one convert the controls from omc to mercruiser controls. i have mercruiser controls and outdrive and would like to mate an omc engine. is this possible.

 

[Lou C]

I don't know for sure what's involved but you'd have to strip off all the OMC rigging and replace it with the Merc, such as the bellhousing, probably the front engine mount, exhaust system, shift linkages, and control. Not sure about the engine wiring harness.
I think the direction of the shifter has to be reversed for Merc vs OMC but it sounds like you're putting the engine from the OMC in a Merc boat, so just install all the Merc rigging and it should work.

 

[Lou C]

One of these days, when I can no longer get Cobra parts or can't get someone to do the drive work I can't do (never needed that yet, the most involved Cobra repairs I have done were the water pump adapter, trim rod seals and steering actuator) I could see myself converting my boat over to Merc. Big job though at my age now. I am surprised though I have had the same drive all the years I have had this boat (23 years in the salt) and that's all it's needed, some seals, bellows 2x, that's it. Regular maintenance really helps.

 

[Bondo]

Does anyone know if you can mate a 3.0 omc engine to a mercruiser outdrive, particulary in the bell housing drive shaft area. can one convert the controls from omc to mercruiser controls. i have mercruiser controls and outdrive and would like to mate an omc engine. is this possible.

Ayuh,...... 'bout anything is Possible,....

What motor was in the boat before,..??
What happened to that motor, 'n it's connecting parts,..??
What model, 'n gear ratio is the outdrive,..??

 

[Lou C]

I think what we need to know is this:
are you putting the formerly OMC engine in a Merc boat with all Merc rigging?
or
putting the Merc drivetrain, etc, in a formerly OMC boat that still has OMC rigging?
Because the one thing I do know about that is the control has to be reversed (FWD/REV). So if the boat you're going to use has an OEM OMC control, it won't work, you'll have to use an aftermarket control that can be adapted to Merc/OMC/Volvo.

 

[jbcurt00]

Isnt the transom thru hole different as well?

 

[Lou C]

The Cobra cut out is identical to Merc

 

[jbcurt00]

The Cobra cut out is identical to Merc

OP hasn't clarified Cobra has he?

 

[Scott Danforth]

Strip off everything OMC on the long block, and build up with Mercruiser specific items.

The motor is a GM 3.0 industrial motor with OMC manifold, carb, and ignition.

 

[Lou C]

OP hasn't clarified Cobra has he?

Good point, I don't know when Merc/OMC switched from the 2.5 liter to the 3.0 liter but the Cobra started in 1986. Not sure if they ever used a 3.0 with the older Stringer drives.
Checked, the use of the 3.0 goes back to at least 1982, before that they are listed as a 120 hp and 140, guessing the 140 is a 3.0....

 

[Scott Danforth]

Good point, I don't know when Merc/OMC switched from the 2.5 liter to the 3.0 liter ....

1990 was last of the 2.5 motors. 1991 is when the new version of the 3.0 was released

Hence the 1990/1991 division

 

[Lou C]

If that’s what the OP has then he should have a Cobra…

 

[Scott Danforth]

Prior threads from the OP have a pre 1991 since the motor has points

Digging further is a 1989 Chap 178 with a busted and welded up Mercruiser 3.0

So @jclark178 , any 1990 or earlier 3.0 long lock only will work to swap over

See post #9

 

[Scott06]

Prior threads from the OP have a pre 1991 since the motor has points

Digging further is a 1989 Chap 178 with a busted and welded up Mercruiser 3.0

So @jclark178 , any 1990 or earlier 3.0 long lock only will work to swap over

See post #9

Pretty sure the only issue he may run into is the coupler , which depends on what generation engine and outdrive he is using. with the 1990/1991 cut over they went from a crankshaft hub bolted coupler to one that bolts to the edge of the flywheel. also Will need to use the merc manifold and exhaust if using merc transom and outdrive

 

[jclark178]

Does anyone know if you can mate a 3.0 omc engine to a mercruiser outdrive, particulary in the bell housing drive shaft area. can one convert the controls from omc to mercruiser controls. i have mercruiser controls and outdrive and would like to mate an omc engine. is this possible.

I"m putting a omc engine in a mercruiser boat. have all the hardware from the mercruiser and aware that it has to be change over from omc to mercruiser. is this doable.

 

[Bondo]

I"m putting a omc engine in a mercruiser boat. have all the hardware from the mercruiser and aware that it has to be change over from omc to mercruiser. is this doable.

Ayuh,...... Should be pretty straight forward,....
What years are they,..??

 

[jclark178]

Ayuh,...... Should be pretty straight forward,....
What years are they,..??

89 model chapparel 178xl