X530 Runs Rough after running under load for 45 minutes to an hour

[howser51]

The X530 starts fine and runs well for about 45 minutes and then starts running rough. Sometimes it comes and goes, but today I mowed two lawns and it did it both times. New plugs, oil changed, and air filter. I added a little Seafood and have been running the ethanol free gas. Any ideas or thoughts as to what is going on?
Thank you
Marty

 

[JD318420]

I would start with checking Plugs, Plugs wires, Coil(s) and igniter probable heat related problems when it happens. Is this a kawasaki?

 

[577jersey]

I had an older Kohler command do that,,it ended up being the coils,,when they got hot they developed high resistance in a wire and it would start to cough,hiccup and act up.
Might even want to check valve lash.

 

[bertsmobile1]

Buy an inline spark tester and run the mower with it in place.
When the engine starts playing up have a quick look at the tester.
If it is also flashing inconsistantly then you have an electrical problem and most likely the coil as previously mentioned .
As these are expensive little buggers it is worthwile checking before you buy a new one as you can not take it back for a refund.