Running with one engine off

[TopShot25]

When I’m going slow, like trolling or pulling lobster traps, I like to run on just one engine. I get much better fuel economy and don’t put unnecessary hours on the engines. Since I don’t really need the other engine anyway it seems to work out well. The only problem I have is that when I’m running my port engine my fuel management system (FMS) is not powered and therefore not working. I’ve tried leaving the key in the on position for the starboard engine and everything works perfect but I’m not sure this is a good thing. So I want to find out what the deal is so I can keep my FMS accurate and not damage anything. It only counts hours when the engine is on, but I’m not sure what else may be on.

Anybody already figure this out?

 

[DaleH]

Not sure on 4-strokes, as I believe some fuel pumps or fuel lift pumps might be energized. But otherwise, on 'dumbb' OBs like my old 2-stroke, once the key is ON, all systems are energized, but the circuits don't know if she conked out or not. Note however, that the hours could FOOL a prospective buyer into walking away.

I'd send an email to Andy @ SIM if I were you.

 

[TopShot25]

Dale, the engine hours don't continue to count, ran it for half an hour and it stayed the same. I was suprised to see that. I guess it could be some kind of smart gauge. I know, wishful thinging. I guess i will try Andy. Just thought someone here may know and I try not to bother him when it's something I think would make a good post.

 

[DaleH]

Newer OB motors drive the hour meter from a green (typically) wire engergized by the flywheel turning. This also 'sets' the computer clock, so when Techs hook up the motor to the computer - they get actual running hours .

 

[Primo]

On mine, the hour meter in the Yamaha tach doesn't register. However, the external hours meter keeps ticking away.

 

[TopShot25]

Andy and SIM replied to me with this answer;

HI John,

You need a gauge power “diode kit” for that FM gauge. This way either engine key switch will power up that gauge with power, without paralleling the two engine harness’s. Make sense?

With all the parts and labor to assemble, you would have about $70 into the harness with shipping. If they used the Yamaha bullet connectors on the gauge wiring, it will be plug and play for you.

Let me know if you have any questions.

Thanks

Andy


Thanks to Andy for always trying to give us a hand.

I think this will be the route I want to go I still have a few other things to work out. I've never been able to get my fuel management gauge to accept speed info from my chartplotter. I followed all instructions from Andy and it just won't work. He says some of the FM gauges wouldn't work. I don't know how this can be, but it appears it must be a few of the older ones didn't work. It frustrates me that they have a setting for it but they won't actually do it.