Please help. I am about to loose all my hair. I did some work to make it better, now this. I have a 24' pontoon with a 1979 merc 175hp 2 stroke. Under a load my outboard will rev up to 3400 rpm and drop back to 3000 rpm instantly. Last year it ran 4500 rpm under a load all day. No load it will rev 6000. I wanted to replace some bad wiring and now this. Here is what I did.
Replace fuel filter and add small inline filter.
Replace the stator, twice.
Replace the trigger.
Replace the rectifier.
Clean and rebuild the carburetors, twice.
Fuel pump output is plenty.
Compression 125 across all cylinders.
Good spark and plugs.
Ohm checked plug wires.
Bench checked coils.
Removed the low idle module, wiring was rotten.
I don't know what to do. Any input is greatly appreciated.
Replace fuel filter and add small inline filter.
Replace the stator, twice.
Replace the trigger.
Replace the rectifier.
Clean and rebuild the carburetors, twice.
Fuel pump output is plenty.
Compression 125 across all cylinders.
Good spark and plugs.
Ohm checked plug wires.
Bench checked coils.
Removed the low idle module, wiring was rotten.
I don't know what to do. Any input is greatly appreciated.