1977 Merc 1150 Random Electrical Shutting Off Issue

[kck8385]

Motor: 1977 1150 S# 4689451

Per the title last fall the motor started to suddenly shut off while under way. By shut off I mean like the key is turned off. No warning, no sputtering, nothing. Just dies. It is totally random and has happened at various speeds. It always starts right back up. Sometime it does not shut off at all. Sometime it will happen a few times in a short period and not again the rest of the day.

I recently replaced the interior and exterior wiring harness as well as the rectifier to see if it would cure it. It did not as it shut off once yesterday. For information the switch box was replaced early last year when the motor would not start.

Could the trigger, stator or ignition switch cause a random failure like I am experiencing? It does not seem fuel related because it is so sudden. Any other ideas?

Thank you,

Kevin

 

[Faztbullet]

Trigger, switchbox or mercury switch.

 

[MH Hawker]

i would take a real close look at the wiring for any thing plugged into the new harness and it could also be in the controler

 

[kck8385]

Faztbullet: No mercury switch. Switchbox replaced last spring. Could it be going bad again this soon?

MH Hawker: All the wiring seems to be in good shape. I rewired the control box when I installed the exterior harness.


Thanks,
Kevin

 

[Gary H NC]

What about the main electrical plug on the engine bracket?
Any signs of corrosion?
I would clean each pin up and make sure the are a tight fit..maybe a little dielectric grease on the plug too.

 

[kck8385]

Gary H NC: I assume you are referring to the interior/exterior harness plugs. The harnesses are brand new and the connections are clean.

Thanks,
Kevin