Weird electrical issue

[Lunchmoney]

Boat parked in freshwater lake for a few days. New twin DF140s. Last night I went down to the boat and figured I'd start the engines and let them idle a few minutes. As soon as I turned the key on the port engine to the run position, both engines started trimming up! I had the binnacle trim switch in the control both motors position so that's why they both moved, but just by turning the key to the run position, no voltage should be going to the trim motors. At this point, I hadn't turned the key far enough to engage the starter when this happened.
I hung and rigged these motors myself about 8 weeks ago. I have about 50 hours on them to date and this is the first time this has happened. I did not replace the binnacle when I repowered. Had to do a little wire splicing for the trims and neutral safeties as the new harness wouldn't plug into the old binnacle but it was pretty simple and everything worked perfectly first time. I'm guessing there's a short in the binnacle or behind the new key switch? The motors trimmed all the way up by themselves and the trim motors kept running even though they were dead heading. As soon as I hit the down trim button on the binnacle, the trim motors stopped. Then they would trim up / down normally. I messed with it a few more minutes and it never happened again.
If I had something wired wrong, this would have happened 8 weeks ago. Weird!

[pniksnut]

i think the trim switch on the binnacle has an issue. water in in or stuck. happens a lot with older switches

[Lunchmoney]

Perhaps but the trim switches are energized irregardless of the key position. As soon as I moved the key switch they started actuating. We did have a gully washer here the other afternoon so moisture somewhere could very well be the culprit.

[Solarman]

I'm thinking a short in the switch itself, do you have the console top mount with the single/dual switch on top surface (facing up)? These switches are very susceptible to rain/moisture collecting inside? Do you have a battery switch, that you turn battery power off/on? Was it off till you came down to idle motors? (A good practice.) Or, one of the two individual handle mounted switches stuck/ shorted/ loose contacts?

True, trim/tilt are normally energized with key off. Is key switch loose, might cause wire movement? Jiggle throttles prior to turning switch on? Wire movement from jiggling? Just some thoughts, i never found a reason for mine. I have been covering my controls since then?

Just curious, about your motors, did you buy online, or local dealer? Ball park price (if you don't mind)? Thinking about doing same? Just comparing pricing. Thanks.
I have had my dual 140's do the same thing, and then act fine after playing with both switches on handles? If it does it again, immediately switch to single motor, this could help find the switch causing a problem.

Good luck. Post back if you find a problem.

[Lunchmoney]

Yes it's a top mount with single / dual switch on the top. Batt switches were on. I didn't jiggle the throttles prior. I'll double check the key switches for for tightness. I want to rule out the trim switches on the handles because it started as soon as I turned the key. It happened pretty quick plus it was dark but seems like I recall as it started coming up, I switched from dual to single and the one motor stopped moving. The other continued to dead head until I hit the down switch on the handle and it stopped. I'll try and think this through...
When I turn the key on, it energizes the gauges, fuel pump etc. It also threw juice to the trim motors either through the binnacle or bypassing it. Seeing how the switch was in the dual position and both motors started trimming up, it had to go through the binnacle... Correct?
I'll send you a PM Solarman.

[Solarman]

Doing over think this situation.
When turning key, because moisture probably grounded single/dual toggle switch, some current feed back to ground activated one solenoid, but because switch was in dual position, activated both motors.

Two things could help here.

1. Switch batt switch off each time you leave boat unattended. Don't think it would have helped, but might prevent electrolysis if moisture does cause a ground short.
2. Cover controls when not used.

As I said earlier post, my twins did same thing, and if I'm not mistaken, I also switched back to single then played with the side still active. Shortly (couple months) after my toggle quit doing dual trim. I removed, to replace the switch, took apart, and found heavy moisture corrosion caused wire terminals to disintegrate. From then i have been covering controls. No other occurences so far, over 3 years now.

Good luck, post back when able to let us know how it's going.

[jHydroman]

I has the same problem on boat with twin DF140's.

Found the port engine trim switch was full of moisture and contacts were shorted out.

Mine actually failed when I was trolling on one engine in thick fog and I was in the shipping lane. I immediately opened the manual lower valves on both engines. The pumps remained running until I unplugged the failed switch.

Jim

[Lunchmoney]

I has the same problem on boat with twin DF140's.

Found the port engine trim switch was full of moisture and contacts were shorted out.

Mine actually failed when I was trolling on one engine in thick fog and I was in the shipping lane. I immediately opened the manual lower valves on both engines. The pumps remained running until I unplugged the failed switch.

Jim

Quick thinking with the manual releases. I'm sure that was a few very intense minutes!