15 hp Yamaha with no spark

Pulse

Recruit
Joined
Aug 14, 2003
Messages
4
Hello.I have a 15 hp Yamaha that has no spark.It's a 1985 sk motor.The kill switch is working as it should and is not the problem.There are 3 wires coming out from under the flywheel,brown(engine start),white/red(coil pulser),and black(ground).When I push an electrical test probe into the connectors the only one that lights up is the brown lead when I pull the starter cord.Should I see some juice coming from the white/red wire when I pull the cord? Could the coil pulser be bad?If so can anyone tell me how to check the coil pulser?Any help would be appreciated.Thank you.
 

blared

Cadet
Joined
Jun 3, 2009
Messages
23
Re: 15 hp Yamaha with no spark

First check your wiring especially the white one and your ignition coil wires which are coming out from your CDI box. Then you need to check your stator and then your ignition coils. Pulser coil just times the ignition spark. your coil wires are blue,brown,red,black/red,red/white, you need to get a volt meter and test the voltage.
 

rons boat

Petty Officer 1st Class
Joined
Dec 28, 2002
Messages
210
Re: 15 hp Yamaha with no spark

Working on same motor and checked the brown wire to gnd and got about 25 V rms or about 40V peak with a positive bias. The trigger shows about 3-5 V and should be enough as these go bad only seldom. Measure from W/r to gnd. Motor had CDI replaced and still no spark. has to be coil so it is on order. I usually use a small C or D cell to flash the primary and this one thought to be defective did not produce a spark as normal.
 
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