130HP Johnson V4 - Stator, sensor coil, power pack - diagnosis

[Striper500]

I recently purchased a boat with a bad misfire. I changed the plugs, wires, and used a new source of fuel to eliminate the easy stuff. My next test was to check the timing. Cylinder 1 and 2 were already marked on the flywheel and appeared to be ok. When I tested cylinder 3 I discovered the potential problem. It seems as though there is no spark going to cylinder 3. The timing gun would not light up, but did on cylinders 1,2,4.
I installed a new coil on cylinder 3 and there was still no read on the timing gun. Just for kicks, I left the plug wire off cylinder 3, and sure enough the motor still sounds the same way. So I am almost certain the timing gun's assesment of no spark is correct.

I was informed by the previous owner that the power pack was replaced last August. I did check the wiring, and it seems to be hooked up properly.

Although I have not ruled out that the new power pack is bad, I am concerned that there might be another problem here, or an issue that may have caused the power packs to malfunction.

According to the service manual, there are a few tests I can perform, but they require a "Peak Volt Meter". Are there any tests I can do without this meter ? Could a bad sensor coil cause this problem?More specifically, if the sensor coil was bad, would it only impact one cylinder ? if so, any tests ?

 

[mankato]

Re: 130HP Johnson V4 - Stator, sensor coil, power pack - diagnosis

Just went through this on my 94 Evinrude 120 V-4. Try this; Remove the #3 plug, then reconnect the plug wire to it. Hold the plug 7/16" away from the head and have someone briefly turn the engine over while you watch for a good, thick spark to jump from the base of the plug to the metal. You should see no spark. Put #3 plug back and try the same test on #1 plug. You will probably see a good spark on #1. If so, swap the wire going from the power pack to the #1 coil to the to the #3 coil. Then re-test for spark on #3 plug. If you now have spark on #3, most likely your powerpack is bad.

 

[flabum]

Re: 130HP Johnson V4 - Stator, sensor coil, power pack - diagnosis

You have another thread with this same problem, here is my response on that other thread:

The stator simply provides the voltage to the pack, if the stator was bad, you would have no spark on 2 cylinders or no spark on any. if the pack was changed on that side, the fair assumption would be either a bad coil (switch it with a known good coil), a bad wire in the #3 circuit somewhere (check all electrical plugs and pins on that side of the motor between the pack and coil and pack and pickup coil) or a bad pickup coil (the part under the flywheel that moves with the throttle. The new pack could still be bad, simply switch them from side to side to eliminate that possibility


Also, don't count out the spark plug, a bad spark plug will make your timing light not flash.