Electric shift stringer/ Stringer 400/ tru course steering compatibility?

[Dirt_Farmer]

I have a 1978 omc 120 with the 400 out drive with tru course steering. Upper gearcase is toasted. I have found a 1973 electric shift with out tru course steering. Does anyone know if I can add the tru course to the electric shift upper and use it on my 400 out drive?


Thanks, Jeff

 

[Howard Sterndrive]

Re: Electric shift stringer/ Stringer 400/ tru course steering compatibility?

trucourse was actually introduced as an option in 1973, so some 73 uppers would have been machined for the internal steering parts, and others not.

but does it have the correct gears in it anyway?

 

[Howard Sterndrive]

Re: Electric shift stringer/ Stringer 400/ tru course steering compatibility?

according to Seloc, your 1978 upper has 21/18 gearing
closest in 73 was the 165 (I6) at 21/19

a 120HP upper in 73 had way different gears (16/20) in the upper.

pair the 1973 120HP upper to the 1978 120HP lower and you end up with a bizarre 2.5:1 overall ratio.... you would never find a steep enough prop to go anywhere

 

[Dirt_Farmer]

Re: Electric shift stringer/ Stringer 400/ tru course steering compatibility?

Thanks, The 73 is a 140 and complete (still in a boat), and my 120 is completely pulled for hull restoration. So I may have to do a complete swap or use my motor with the electric shift out drive.

Thank again, Jeff

 

[Howard Sterndrive]

Re: Electric shift stringer/ Stringer 400/ tru course steering compatibility?

So I may have to do a complete swap or use my motor with the electric shift out drive.

that could work, if the 73 drive is low profile (rare in 73 - the first year for the low profile option) and the upper is machined for tru course steering parts (unless you want to mount that old push-pull steering in your hull.... I would be cautious with that - the omc push pull external steering cables are no longer avail and the length would have to be right for your boat)