Mercury ELPTO 115 burnt wires????

[Freetrilly]

Hi,
I have a Mercury ELPTO 115, it's a 2+2 type engine 2005. 2 stroke at low rpms and then 4 stroke at higher rpms. It is attached to a Tracker proguide v-17.

This morning I had the boat out on the water and everything ran fine until I got out of the water and noticed oil on the ground under the engine. I traced it back to a hole in the oil tank that was caused by what appears to be a short in some wires that touch the oil tank.
The engine ran fine all day, about 2 hours run time with starting and stopping.

Any help as to why and how to fix would be appreciated. It doesn't look like wires for the starter.
Here are some pictures.

 

[Texasmark]

Fist off a moot point. The 2+2 is a 2 cycle (stroke) engine with 4 cylinders. With speeds below around 1800 RPM there isn't enough fuel pressure to supply the bottom 2 cylinders with enough fuel to ignite and produce power. Above that "kick in point" all 4 (the other 2 kick in and) produce power.
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Have you had starter "Bendix" sticking problems", or have you had problems starting whereby the starter kept turning after you released the key? I would think that you would have seen or smelled smoke and noticed peculiar operation during the day's outing if that was the case....

Examining the black heat shrink just to the left of the plastic red cap over the Starting Solenoid input 3/8" copper stud, surrounding the multitude of red smaller wires for power distribution, it appears that there are marks that weren't there when the engine was built, like maybe some holes were burned in the plastic tubing...ref pic 3. That will support what I am about to say.

I also noticed that yellow heat shrink on the output terminal of the Starter Solenoid (terminal immediately above that one), appears to be damaged also....assuming the blacking on the shrink is water proofing spray on the terminal after it was assembled. Noting the other end of that same wire the same thing in terms of possibly excessive heat.

Knowing all the wires that were burned and which one burnt which other ones would help. The white with green stripe and green (with white stripe you can't see) are capacitor charging power lines from the stator and probably not capable of causing the problem in my (unfounded) opinion. Can't recognize the other small wires. It would help if you would remove the tank and separate the burned wires and tell us what you see.....really confusing since you said he engine ran ok...wouldn't run ok if the cap charging wires weren't supplying power to the CDMs...like burned open or shorted out. The large diameter, black battery power wire, possibly could if the Starting Solenoid stayed energized...like would happen when internal contacts get worn, material is depleted and what's left welds together and continues to supply power to the starter.

The other problem is that the wires appear to be pinched in that area. which would aggravate an excessively high current condition in any wire.

I'm dressed for bed, had my bath and it's 95F outside. Otherwise I'd go out to my shop, to my 2+2 and look over that part of the wiring harness and see what I can learn.

Maybe tomorrow, nothing pressing.

 

[Freetrilly]

Hi, really appreciate your detailed response!

Did not notice and odd issues with he starter or Bendix issues. Thinking back, after running the engine for about 10 minutes on the water, it was hard to start back up. I had to turn the key 5 or 6 times before it would start. Never cranking for longer than a few seconds though.

I will get that tank off and show the separated wires.

 

[Freetrilly]

Had some time to tinker and was able to pull back the oil reservoir and get some pictures of the burnt wires.
It looks like one of the bullet plugs was more of the culprit for short/ burning (picture 3).

The repair shop is about 1.5 months out and would like to get this fixed asap. Could I just splice the burned wires with new 14awg and also replace the larger black ground wire and be good to go?