X500 Will not start when hot - please help

[PatentGuy]

I have a X500 with 330 hours that will not start when it is hot, until it cools off - then it will start. I have removed and cleaned the fuel tank, replaced the fuel filter, replaced the fuel pump, replaced the plugs, and checked the gap between the flywheel and the coils. However, from what I have learned since, the gap between the flywheel and coils is irrelevant, as if the problem is electrical the engine will shut down sometimes when hot - which it does not do, so that should not be the problem. It will run as long as it has gas once started and will start whenever cold. Engine is carbureated twin cylinder Kawasaki. I presumed this is the problem of insufficient fuel pressure to push out the gas vapor created in the bowl when the engine is hot but not running - however, this does not seem to be the case at least external to the carburetor as fuel flow is good.

I presume there is a carburetor issue, but wanted to ask the experts before getting into that. Been a few decades since I took a Weber apart and had a bad time with quadrajets...

Any help greatly appreciated

 

[tomplum]

To narrow this down, what is on the need to know list is does this have spark at the plugs when it doesn't start. I'm assuming that it cranks and doesn't start here. If you have a decent spark tester, great. Otherwise have an old spark plug with you and ground the base , set the park brake and give it a crank.

 

[jaxs]

You might be on to something when suspecting vapor in carb/fuel line. Try cooling line and carb with wet cloth. Be carful not to wet hot engine parts that might crack. If carb has a vent (which most do) the vent might be stopped up.

 

[PatentGuy]

Thank you. Been meaning to get a spark tester and will do so and be sure. Should not be the problem because it doesn't die intermittently when hot, but I understand the knowing concept.

Would have never thought of cooling the carb with an ice towel, great idea, will try that when I can. Unsure on the vent, just do not know and lack a factory manual.

Will be awhile before I can get back to this, but will and report back.

 

[RBLapham]

My X300 should be quite similar as it has a Kawi engine. Mine will not start when hot unless I choke it!. The manual says to choke it also hot or cold. works every time. If it was hot and only turned off for a very short time(a minute or 2) it may start without the choke.

 

[Amvcane]

Fuel cap venting properly?

 

[PatentGuy]

Thanks guys. It will not start when hot choke on or off. Will pull the cap next time and see if that helps, but if that were the problem I would think it would die after being used awhile, but will check when I can get back to it.

 

[dieselade]

have you thought about the electronic control module? I just done that to mine early this month.

 

[PatentGuy]

I have not, unsure of how to diagnose that. Wasn't aware it had such a module. If that could be the problem then I guess it's time to take it to the dealership. But I continue to believe a fuel vapor lock situation of some form is more likely.

 

[dieselade]

my x500 would just up and die and backfire after awhile of mowing. would restart on i would mow and then die again. May not be your problem if it is not randomly dying. It is sort of easy to replace this module. just google "john deere mower x500 keeps dying." so you might have a different problem.