!973 OMC 225hp sterndrive w/ electric shift and binnacle mounted shifter

fdresser

Cadet
Joined
Jun 15, 2013
Messages
10
I lost the ability to shift in to gear while under way. Both forward and reverse simultaneously.
I have disconnected the knife connectors at the port side of the engine and with an OHM meter gone from the forward and reverse wires individually with the red prong and to the negative battery terminal with the black prong. I got readings around 2.6 to 2.7 for the blue(reverse) and slightly lower 2.3 to 2.4 on the green(forward).
Does this reflect a shorted coil or lead, which is what the manual indicates and what would be your next step?
Thanks for any advise
 

Howard Sterndrive

Rear Admiral
Joined
Nov 5, 2008
Messages
4,603
Re: !973 OMC 225hp sterndrive w/ electric shift and binnacle mounted shifter

could be a lower unit full of water combined with failing insulation on your coils or wiring. New type C gear oil has low conductivity, so a few pin holes in the insulation won't be an issue.

When you touch the two leads of the meter together, does it read 0 ohms? That will test the accuracy of the meter. I'm a bit suspicious of your meter giving such consistent readings on both F and R circuits. If the meter's good, I'd focus on the gear lube.

If milky, try a flush with cheap clean oil, then new type C. If it shifts again, then a lower unit reseal is the fix.
 

Howard Sterndrive

Rear Admiral
Joined
Nov 5, 2008
Messages
4,603
Re: !973 OMC 225hp sterndrive w/ electric shift and binnacle mounted shifter

and if the meter turns out to be off and the ohms are correct, then the next questions are:
any unusual grinding?
and did the engine start to overheat after propulsion was lost?

and the propeller hub would be something worth checking. Rotten rubber will let go after a couple decades.
 
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