15hp evinrude coil on a hydro

[newbieonthewater]

my brother races a hydro he is having problems with getting power top speed 44 mph with a restrictor plate he has a rebuilt carbuerator while reading on another forum their was a question about bad coil or good coil it said while the motor is running pull the spark plug wire if the motor dies you have a bad coil is this true or not. also while racing yesterday on the last heat when we got the boat back on the sand their was oil all over the motor and it was coming all the way down the shaft don't know if that is the write term i was told that can be normal i got people telling me something is wrong with the motor but i have the guy who rubuilt the carbuerator telling me nothing is wrong with the motor you just need better props any advice would help thankyo

[Kev43V]

in my humble opinion:
coil: when you have one bad coil and the motor is running on one hole. pulling the spark plug wire from the good coil will cause the engine to die.
pulling a wire from a bad coil will result in negligable change in rpm. if this happens you either have a bad coil or a bad electronics. It is USUALLY the coil.

oil running down the tower: this is ok or bad depending on the mixture you are burning:
if you are not getting good combustion in one cylinder (IE bad coil or some other ailment)
you will get unburnt fuel oil mixture running down the tower.
yet you can have a good burn in both cylinders and get some oil if you are running a very oil rich mixture.
put a test wheel one the motor. warm it up, then run it wide open for at least a couple min. kill it by pulling the kill switch with the throttle wide open . check your spark plugs: ( killing the motor with the thottle when you intend to read the plugs is a bad idea as they will "read" leaner than it really is)

remember it is not really unusual for a bad coil to work just fine when cold. but by the time you are half way done milling it starts to malfunction.

dysclaimer I am probably the worst motor mechanic in the history of outboard racing LOL

btw if you have recently increased the amount of oil you have been putting in your fuel it is expected that you will have to increase the heat range of the plugs you are putting in the motor to get that mixture to burn properly