76 mercury 50 hp slow down

[ilovefishing]

i have a 50 hp mercury 4 cylinder 2 stroke motor. symptoms are runs 3/4 mile or so on full throttle then it idles down to about half throttle. i have replaced all gas, fuel lines from tank to motor and even lines inside motor, spark plugs. same sytoms. while getting frustrated openend the motor again and found that the positive wires feeding the 4 coils are corroded and one was almost fell apart. I haven't replaced them yet(tommarows project) my question is could anyone comment if i am going in the right direction. this is what puzzles me is that its an intermittant problem, seem when it heats up it does it more(With how bad the wires look,one of them looks like it's melting the rubber coating from the inside. Idles and starts fine. thanks for any input

[Surface Tension]

I think your looking in the right direction. Replace the wires. Bad electrical connections will produce heat.

[marine_man]

I'd also agree that you're headed in the right direction. When the motor heats up things expand, sometimes causing gaps in wires that sparks used to be able to jump to be too large.

At a minimum you've ruled out the wires as the culprit if it doesn't fix it.

marine_man

[ilovefishing]

well just to give everyone an update, i replaced the wires from the magneto to power box(wires also from power box to the coils) i think thats part of the problem, but the one thing I found is that the top carburator float is split in half and is sticking in the up position. the bottom float is cracked(so i will be replacing them also. any suggestions where in the hinckley area i could find floats?

[marine_man]

Mora Marine in Mora should have parts...

marine_man