1976 Mercury 850 engine wiring issues - 105 hours only, too good to junk?

[Aussielad]

Greetings from Australia.

I've been tasked with returning my elderly father in law's boat to a going concern, he has owned it from new, 105 hours of fresh water use only. It has not been used for the past six seasons, marine mechanics around here aren't real interested, too old to bother with.
Engine starts and seems to run OK until throttle is opened to the point where ignition and throttle advance engages, then just bogs down.
Engine serial # is : 4368089
So far I've discovered:
Majority of engine wiring is perished
Battery is not charging
Tachometer is erratic
There is evidence of rubbing on the stator plastic covering and some of the flywheel magnets.
Given the components are 40 years old, I'm thinking my best option may be to just replace the engine harness, stator, trigger, switch box, and rectifier, I'll need to order from the US. I have not been able to source the ground or ignition harnesses.
Does this sound like a sound strategy?
I'm concerned about the stator rubbing, any tips would be very much appreciated.

Cheers
Reg

 

[Chris1956]

You probably need to replace the engine harness. They are avail in lots of places, so look around for a good price. That motor is 4 coil right? I would hold off on the other components, provided their wiring is good. If their wiring is NG, replace them. The stator should not rub the flywheel. Find out what is going on there.

I think you will end up cleaning and rebuilding the carbs with new floats, inlet needles and gaskets. Toss in a new fuel pump rebuild kit.

 

[Aussielad]

Thanks for your input Chris,

Yes, four ignition coils, I intend to renovate carbs, hoping I can find spares here, wiring from stator and trigger is shot.
I now suspect the rub marks on the stator and flywheel were caused by an old wasp nest, there was one behind the dash, apparently after it was first started recently a lot of 'dirt' was discovered under the top cover, Euro wasps are becoming a real problem here, boat is 3.5 hours drive from me, I'll get stuck into it in a few weeks time .

Cheers
Reg

 

[merc850]

Carburetors really only need cleaning they tend to last a long time, one quick way I have of checking them out is to tip the motor up onto the lock then pump the fuel bulb and see if gas comes out. This can help unstick floats etc.