OMC Outdrive Mid 70s

[Bob1944]

Can I use a mid 70s omc outdrive from a 4 cyl on a mid 70s omc straight 6 cyl engine?

 

[Master of the Boat]

Re: OMC Outdrive Mid 70s

1975 140 upper:19.20 lower:15.23 total:62 overall:1.61

1975 165 / 175 / 190 / upper:21:19 lower:15.23 Total: 72 overall: 139

You decide. Maybe someone else can chime in, if you can make up the difference with prop pitch, i don't think so.

 

[Bob1944]

Re: OMC Outdrive Mid 70s

I have not taken my old one apart yet. All I need is the housing which connects to the trim gear. Can I use the housing from the four cyl outdrive and put the gears from the six cyl outdrive in that housing so I have a good trim gear?

 

[Master of the Boat]

Re: OMC Outdrive Mid 70s

You mean the tilt gear? Because this drive can never be run except fully down or you will eat the ball gears in no time.
And yes you can change it out will fit. This is electric shift outdrives correct?

 

[Bob1944]

Re: OMC Outdrive Mid 70s

yes, the tilt gear. and yes, both are electric shift. I can get the entire donor boat for 300 including the trailer. I think I can sell the trailer for 200, use the seats in another project, and maybe sell the 4 cyl engine and some other parts from the boat and use the other parts in various projects. Maybe sell the lower end of the outdrive too.

 

[Master of the Boat]

Re: OMC Outdrive Mid 70s

You intend to keep this boat then i would in your position horde the lower, and intermediate, the drive shaft, coupler, and any other part, that is not the motor itself and says omc on it. The coupler and the drive shaft are known to go.
The motor sell. The bell housing / adapter keep. The shift wire keep, the buttons and or shifter keep. The steering parts keep. You have a external steering bracket / rod ? Keep.

 

[Bob1944]

Re: OMC Outdrive Mid 70s

wow, thanks for the excellent advice!!!

 

[Master of the Boat]

Re: OMC Outdrive Mid 70s

The master is pleased that he was able to help. He would also help in any small way if in the future you post for assistance.

 

[Bob1944]

Re: OMC Outdrive Mid 70s

thank you, you obviously know a lot about outdrives.

 

[WizeOne]

Re: OMC Outdrive Mid 70s

....The coupler and the drive shaft are known to go.....
..

If you ever have an early coupler go, you can upgrade to the later ('78 & up) larger splined drive shaft and coupler. The electric shift couplers used too fine a spline and were prone to wearing out. Thankfully, mine lasted 30+ years but when I had the motor out for floor work, it was obvious it wasn't going to last much longer.

 

[Bob1944]

Re: OMC Outdrive Mid 70s

great information, thanks

 

[Bob1944]

Re: OMC Outdrive Mid 70s

OK, anyone know the gear ratios between the 1976 OMC inline 6 and a V8?