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Hello

I got a problem with my John Deere F510 Kawasaki PA420A.

It starts perfect when the engine are cold but when it get warm I can't start it again before it cooled down.
Also it sometimes die when mowing, last time it died and backfired at the same time, it also lack power but only when the blade are engaged.

I have cleaned the carb and changed the fuelfilter so no problem there, and the fuel line is not hot.
A compression test on warm engine is 150psi.
If I spray some fuel or engine start in the cylinder it will not start.

What do you think about coil issue ?

Sorry for my bad english, it is not so good but I hope you understand

Does sound like a coil issue....also check the tank vent.

I have looked at the cap, it says "not vented" so I found another place on the tank where it's vented and I added some air to it, no problem there :confused2:

can I test the coil somehow?

Okay I just saw something funny :/ cold engine starts perfect, power lack when warm and can not start when warm..

So I testet the spark against the engine when cold, perfect spark,, I then started the mower and used it for about 15 min so it was warm,, I turned it off and again could not start, so I testet the spark plug again on hot engine, and no spark at all.. when the engine started cooling down I got a spark that got better and better.. Isn't that a clear sign of the coil or could i be anything els ?

Yes you can check them...

next time you have no spark, turn the key off and then back on to see if spark is back....sometimes a key switch can go bad. do it two or three time to see..

I did switch the key on and off, no effect..

The control unit, is that the ignitor?

Hmm, I have absolut no idea what's wrong :/ I've borrowed a key switch and a PTO switch from another mower, I've replaced the ignition coil with a new from John Deere and I still got no spark when it's warm.. Do anyone got an idea ?

See if you can find a wiring diagram for it.

You can also check if there is a relay inline with the kill side which may get hot and cut out.

I’ve have tried google but I can’t find anything but a general wiring diagram but that isn’t for the f510.. I will see what I can do

I have also been looking and can't find one anywhere, this is from a repair PDF file that I have.......

When the operator rises from the seat, the seat switch contacts open, causing current to stop flowing to the time delay IC. If the operator does not return
to the seat within approximately one second, the time delay IC stops current flow to transistor. The transistor will “switch off”, causing current through
relay coil to stop flowing and de-energize the coil. With the coil no longer energized, relay contacts will open. Current stops flowing to the ignition coil, thus stopping the engine.

NOTE: Driving the machine over rough terrain can cause the seat switch contacts to momentarily open and close. When this happens, the time delay IC allows the engine to operate without interruption.

If the operator returns to the seat within approximately one second, current flow is re-established to the time delay IC before it has a chance to “time out” and stop current flow to the transistor. Current flow is NOT interrupted to the ignition coil and the engine is allowed to continue operating.

So if you haven't already done so, check out the seat switch, making sure it works all the time.....

Hmm not the seat switch, it’s no so taking the wire off the seat it will still be able to start, when the seat switch is active it will ground the igniter causing the engine to turn off, like the pto switch also will. Anyway I just maked my own test wiring just for testing, after that the original will be put back on again.

I took a wire from the ignition coil terminal to the igniter terminal and from there a wire with a switch to ground so I will be able to turn of the engine by grounding. Anyway I got a spark and the engine starts but again only when cold. But I maybe found the problem, by doing the rewiring I had to remove the igniter from the engine and ground the case somewhere else causing the igniter not to get so hot while no attached to the engine cover, the engine can not start after 10 minuets and not one or two hours, and by thinking logic then I have isolated the ignition circuit only with the coil, spark plug and igniter, spark plug and coil are brand new so could it be the igniter with that in mind ?

Have you check the fuel shut-off solenoid when the engine stops, (is it still on)

Yes it is activated and open, that I have checked:/

"so could it be the igniter with that in mind ? "

Try using some Fault Detector Freezer Spray......."Applying to electronic components will lower the temperature of the component. Any faulty overheating component will cool and return to correct operation, thus indicating the faulty component."

I am going through the files that I have with John Deere, because I have read you can use other diagnosis of other models, but am on other forum's so I come in here now and then at times.

If that doesn't work, remove the engine cover and the remove the kill wire from the coil(s) will it still run after that.