Kawasaki FH601V spark problems.

Rodney51Cub · Dec 3, 2021

FH601V-DS06 in a Toro ZTR will not run on #1 cylinder when the kill wire is connected to it and #2.

If you pull the kill wire off of either coil it will run fine. It does not matter if the kill wire is unplugged from the mower or not.

First off I inherited this project and do not know the original problem other than low power.

Both coils are suppose to be new. There are no diodes in the kill wires at the engine. No chaffing or bare spots in the kill wire that I can see.

The coils are an upgraded part from the originals.

Valves have been adjusted and compression is 90 psi on both cylinders. According to the manual compression is good.

I have not driven it with wires disconnected but it sounds good and responds well to the throttle.

I am thinking I have a bad coil but would like a second opinion before I purchase another coil.

T.R.K. · Dec 3, 2021

Instead of the diode being in the kill wire, it is in the coil. Each coil has a diode in it.

The catch is I am thinking you need to replace the #2 coil as a bad diode in it will kill the spark on #1 cylinder.

On further thought: I remember an older Toro several years back that would run fine if the kill wire was disconnected from the chassis
wiring harness, (disconnect at the plug that comes out of the engine) but would skip or run on one cylinder occasionally with the wire
hooked up. Replacing the delay module fixed that one. I thought at the time the delay module was giving the kill wire to the engine to the
engine a partial or occasional ground.

If the engine has a fuel solenoid, you can test run the machine with the kill wire disconnected. Just be aware that none of the safety
switches will be working. So I don't recommend extended running like that. The engine will starve for fuel about three seconds after the
ignition switch is turned off.

Rodney51Cub · Dec 3, 2021

I have run the mower with the kill wire disconnected from the harness and it still misses when both coils are plugged into the kill wire.

As soon as I disconnect either coil the engine straightens out. I was thinking #1 coil was the problem.

What you are saying about the #2 coil diode makes sense. I will get a new coil tomorrow and try it again.

Thank you for your time.

Rodney51Cub · Dec 4, 2021

I replaced #2 coil and the engine runs as it should.

Now I have to replace all three idler pulleys on the deck, they are louder than the engine.

Thank you for your time.

wore out · Dec 4, 2021

(quoted from post at 14:56:50 12/03/21)

Apparently, the internal diode must have shorted.

It would have been interesting to connect a diode in the "kill" wire to that EI unit and see if that would have solved the problem without the expense of an EI unit, probably would need to try the diode connected both ways to get the correct polarity.

Kawasaki FH601V spark problems.

Rodney51Cub

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T.R.K.

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Rodney51Cub

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Rodney51Cub

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wore out

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