1997 Mercury 40 ELPTO Burned Rectifer

[Rusty Boater]

1997 Merc 40 ELPTO
Serial # 0G555944


I just bought this boat and the third trip out I smelled a electrical burning smell. Never smelled it before. The motor cranked and ran fine.

Got the boat back to the house and took the cover off the coil and electrical area and found a hole burned in the middle of the square circuit board with two yellow, two red, and one grey wire coming out of it. When the motor is started it glowed orange like the end of the cigarette, scary stuff!!!!

Research seems to call this a rectifer. I had the battery out eariler this week to fix the strap that holds the battery in the tray.

What would cause this and what else this and should i look further than the rectifer. Thanks for the help!

[MacDaddy21]

I have heard that hooking up battery terminals backwards can do this instantly, also have heard that a short in the wiring can result in a fried rectifier. I would check all connections around your solenoid and other components.

[Rusty Boater]

The battery cables were connected correctly. All conncetions appear to be tight. Any other ideas?

I want to make sure I do not just burn another one up.

Thanks for the help guys!

[carholme]

Rusty;

Your engine comes up as a model:

1040412TN MERCURY 1997 40

Parts listing:

http://www.crowleymarine.com/mercury-outboard/543.cfm

Service manual:

http://1manual.com/Mercury%20manuals...76r1/cover.pdf

Gerry

[Rusty Boater]

It is not a jet drive but I suppose that does not matter, correct?

[carholme]

Rusty;

No as it covers both.

Gerry

[sxmerc]

I have seen dirty cable connections at the battery responsible for this, and I have also seen a weak or broken spot in the cable themselves responsible. Take cables off of battery, and feel the cables for any lumps or soft spots along their length. Clean cable ends (till they shine) and battery posts, and reconnect to battery and tighten with pliers or wrench. Dirty or loose ends create resistance, resistance creates heat. Hope this helps.