93 Yam 150 w/ no spark on Cyl #2 and #5

[Realitycheck]

I ran out of gas last week and had to get some brought out to me. (I mix my gas in the tank so I don't even use the VRO). The boat wouldn't get above 6kn coming back to the hill. It used 5 gallons of fuel in 5 miles and I had to get towed the last mile and a half. When I got it home, I found out why. The #2 and #5 Cyl have no spark at all. I tested the wire coming into the coils and it is dead. If I plug either of the coils into another wire, they spark. It appears to be something in the CDU. Is there a failsafe that needs to be reset? Is the CDU burned out? and if so how would running out of fuel do that? Any ideas?

 

[rodbolt]

Re: 93 Yam 150 w/ no spark on Cyl #2 and #5

using that much fuel you may have a damaged fuel pump.
how are you checking spark?
test spark correctly, if no spark on 2 and 3 test the pulsr coil inputs to the CDI.

 

[Realitycheck]

Re: 93 Yam 150 w/ no spark on Cyl #2 and #5

I'm testing the power coming into the coil with a meter. By pulsar coil, are you referring to the three coils on the throttle advance under the flywheel?

I assume that each of them runs two cylinders and that the same one feeds the input to the CDI for cylinders 2 and 5. Is that correct?

Am I to assume that the output from the pulsar coil that is bad (or broken connection) would be obvious when the wire is tested for voltage coming out and going into the CDI?

 

[rodbolt]

Re: 93 Yam 150 w/ no spark on Cyl #2 and #5

yes each pulsar controls the triggering of 2 cylinders, the two charge coils provide the capacitor charging curent.
what kind of meter are you testing primary ign coil voltage with ?

 

[Realitycheck]

Re: 93 Yam 150 w/ no spark on Cyl #2 and #5

Rodbolt,
You hit the nail on the head once again!
I pulled my flywheel off and found one of the pulsar coils to be broken. After swapping a good one off a 225 I have for parts, I now have fire on all cylinders.
Thanks,

 

[rodbolt]

Re: 93 Yam 150 w/ no spark on Cyl #2 and #5

one would almost think I have done this stuff before.
glad your back in action.