Mercruiser 120 High Voltage Draw When Changing Gears

[lognum]

Greetings,

I have a 3 Buoys SunSport Houseboat with an Merc 120 (1986). The gear shift is electronic. When switching from neutral to reverse and back through to forward, the voltmeter on the dash drops to 10 and there is a delay in switching gears. At times, it won't switch out of forward and the voltage draw on the meter stays at 10. Looks to be under heavy load. Any suggestions? I hooked up another 12 volt battery under the helm, right to the voltmeter, with a switch, so that I could boost the power. It has helped a bit, but then sometimes the engine quits when changing gears. Thanks.

 

[alldodge]

Greetings,

I have a 3 Buoys SunSport Houseboat with an Merc 120 (1986). The gear shift is electronic. When switching from neutral to reverse and back through to forward, the voltmeter on the dash drops to 10 and there is a delay in switching gears. At times, it won't switch out of forward and the voltage draw on the meter stays at 10. Looks to be under heavy load. Any suggestions? I hooked up another 12 volt battery under the helm, right to the voltmeter, with a switch, so that I could boost the power. It has helped a bit, but then sometimes the engine quits when changing gears. Thanks.

Noticed the post this morning and was hoping someone which knew more about the electric shift would come in and help. Hope others will come in, but from my looking around the motor does not fail very often, yet I will say that if there is a higher then normal current draw then the motor may be the issue. I would look real close at all connections, most all cases with electrical circuits is corrosion.

Putting an additional battery close under the helm should have helped but with the engine quitting, my first thought would be there is a corrosion issue going on, because this should not happen. Start with the battery cables and note both positive and negative cables.

 

[Bt Doctur]

consider replacing the shift cable and . cleaning the shift motor connections. this is the latest pic I can find. from manual2 1974-1977 no electric shift was used in your year that I can find.

 

[lognum]

Thanks guys. I will try the recommendations and let you know.