Weak spark on a 15hp

[Breynolds]

I have a 1986 15 hp Johnson that I am having a hard time starting. The spark air gap according to the book is 1/2 inch. I am getting about 1/4 at the most. That is when I pull it as hard as possible. If I pull it half heatedly I get no spark at all. The charge coil ohms out at 540 ohms. Sensor coil is 40 ohms these are in spec and so are my 2 ignition coils. I really don't have a way to check the voltage. Could my charge coil be weak even though it ohms out ok? Anyone out there have any suggestions?

 

[marinemech1]

Re: Weak spark on a 15hp

does it spark ok with plugs out?
if so your charge coil could be weak or power pack is at fault.
you probably don't have a peak reading voltmeter??
but if you do you can measure charge coil and power pack out puts.
sounds like pack may be at fault.Does motor eventually start and run ok??
Wayne

 

[Breynolds]

Re: Weak spark on a 15hp

It sparks the same with plugs in or out. It will eventually fire but it doesn't run good. I will get hold of a peak reading meter and check my output. Do you know roughly what it should be?