Strange Z Force S Kawasaki starting issue

[petermac]

My daughter has a 2008 Z-Force S that I gave her after I upgraded to a commercial model. It has a 22hp Kawasaki FS651V engine.

It started fine this year and she mowed with it a couple times. Last weekend it wouldn't start. She would choke it, crank it and it would sputter and die. The throttle lever didn't seem to have any effect. I immediately thought it was the usual ethanol/carb gum thing so I went over and replaced the fuel filter, cleaned the air filter, took the carb apart, cleaned it, reassembled and no better. Same deal. I added some Seafoam, cranked it a few times and told her to let it sit overnight.

Next day, no better. So I took the gas tank off, dumped it out (along with a red gas container nozzle cap and another small piece of white plastic), refilled with fresh fuel and a little dab of Seafoam for good measure, choked and cranked, choked and cranked, then it sputtered and came to life. Ahah! Success. I mowed for about fifteen minutes, ran fine, so I parked it in her garage so she could finish the lawn.

She got home from work and it wouldn't start. Same drill. So I went over and noticed what appeared to be a mouse nest under the cover, left side. Took the cover off, removed the nest (it didn't look like it was inhabited very long), looked for any chewed wires, etc., couldn't find anything. Put the cover back on, choked and cranked, choked and cranked a few times, then it sputtered to life. She finished mowing her yard, brought it in and parked it. Wouldn't start again.

So, I (think) I have eliminated the carb, fuel filter, air filter, fuel quality. Fuel solenoid is clicking. Haven't done anything with the fuel pump. Don't know whether the mouse did any mischief. Any suggestions what to try next?

 

[rcbe]

would try spraying a cuppla shots of rattlecan carb cleaner down carb throat while cranking normally - if engine pops, you still have a fuel delivery problem. If not, ign or mechanical.
Then would check for good bright blue spark with tester....mouse could have chewed anywhere on ign circuit...

 

[Coyote machine]

Verify ignition: strong spark, not dropping out while cranking. Could be flakey ignition module, (whatever they use to provide spark/timing sequence).

 

[Navasot]

The fuel shut off can be clicking but the needle may not be moving enough.. take it out and push on the needle to see if it will go down and bring itself back up again with ease. if it feels gummy you can clean it out as well. Also how did you clean the jet? just spray it down or did you actually use something to push the mess out? Cranking with choke but not runnin usually points to the jet.

 

[petermac]

The fuel shut off can be clicking but the needle may not be moving enough.. take it out and push on the needle to see if it will go down and bring itself back up again with ease. if it feels gummy you can clean it out as well. Also how did you clean the jet? just spray it down or did you actually use something to push the mess out? Cranking with choke but not runnin usually points to the jet.

I just sprayed out the jet, didn't use anything like wire to mechanically ream it out. I'll try that today. Might take it into the dealer and put it in his ultrasonic cleaner too, while I'm at it.

Checked the spark and all seems OK with that.