A Ghost Started the Engine?

[Gabrieln]

I got the most awkward call at 4:00 am telling me my engine started itself and ran for ~45'.
I had the boat hauled out and, since the solar controller isn't working, she was plugged in to charge the batteries.
Maybe the panel switch got shorted due some severe corrosion, maybe it's the starter relay that it's corroded/shorted.
Don't know much about engines or electrical systems and my english isn't good enough to express myself on such confusing subject.
Anyway, any help to decipher this mystery is more than welcome.
I'm afraid that after facing (optimistic mode on) a burned out starter, exhaust, raw water rotor, etc. and the bovine look on the marina's people I won't have the necessary serenity to think clearly.

PS: I won't be offended in any way by any kind of remarks. I recognize my ignorance and try to learn from any opportunity and mistake.
Just shoot! :-)
PS2: It's a Volvo MD2020 in very good condition (I assume).

[Rakuflames]

Originally Posted by Gabrieln

I got the most awkward call at 4:00 am telling me my engine started itself and ran for ~45'.
I had the boat hauled out and, since the solar controller isn't working, she was plugged in to charge the batteries.
Maybe the panel switch got shorted due some severe corrosion, maybe it's the starter relay that it's corroded/shorted.
Don't know much about engines or electrical systems and my english isn't good enough to express myself on such confusing subject.
Anyway, any help to decipher this mystery is more than welcome.
I'm afraid that after facing (optimistic mode on) a burned out starter, exhaust, raw water rotor, etc. and the bovine look on the marina's people I won't have the necessary serenity to think clearly.

PS: I won't be offended in any way by any kind of remarks. I recognize my ignorance and try to learn from any opportunity and mistake.
Just shoot! :-)
PS2: It's a Volvo MD2020 in very good condition (I assume).

Clearly, the explanation is in your title!

[roverhi]

On my Yanmar 3GM30F, the hotwire to the starter solenoid is extremely close to the starter actuator terminal. Something less than a 1/2" separates the two. If the ring terminal on the hot wire is loose or installed oriented just a little to the left, the engine will start as soon as the boat main switch is turned from off to either of the three energized positions. Scared the hell out of me after I did a reinstall of the engine and it fired up as soon as I moved the battery switch from off to position 1.

Can't believe that Yanmar would design the starter connections with so little space between them and so prone to accidental contact. Perhaps it's not only Yanmar that does stupid things. Check your connections to the starter to be sure they aren't accidentally making contact with something they shouldn't.

[Jesse]

I definitely agree with roverhi's solution. It's a shame about the peripheral damage.

[transmitterdan]

A boat engine should always have the battery switch set to off when you are away. Especially so when on the hard. Important circuits such as bilge pump should not go through the engine battery switch. They should have their own switch and circuit protection. Then this issue can only arise in your presence. It is not uncommon.

[Hudson Force]

About 15 years ago I met a couple in Marsh Harbor in the Abacos that had a combination fire and engine start while sleeping aboard in the slip. Caution must be taken to assure that you are not "hot" and ready to be underway!