Z122R stops running after about 1 hr

[NormanB]

I bought this ZTR 10yrs ago (less than 400hrs) and it's run great until this spring. Recently it will run fine for about an hour at full throttle(~3,000rpm) then sputters and dies. If I let it sit overnight it will do the same thing the next day. If I run it at 2,600rpms it will run longer but still dies after about 1.5hrs. I can sometimes keep it running with the choke but it still wants to die after about 2hrs. If I disengage the blades when it begins to stutter it will often resume running normally without dying. I have replaced the fuel and air filters and checked the fuel line. And the last 2 wks it has started to smoke (blue) when I start it I change oil regularly.

Any ideas?

 

[Auto Doc's]

That has the signs of a failing ignition coil when hot. Just the same, a spark plug could also be breaking down and plugs are easy to replace.

When it acts up, use a spray bottle to shoot a stream of water on each exhaust pipe near the cylinder head. The water should burn off quickly if the cylinder is working, if the water does not burn off quickly, that would be the cylinder with an ignition spark plug or coil failing.

Use only a genuine Kawasaki branded coil (If it is the coil failing). Amazon coils are junk right out of the box in most cases. The same goes with spark plugs, get them from a local parts store and make sure the numbers match. Don't except the "it will fit" story when it comes to spark plugs. Spark plugs have different heat ranges that will affect the running performance.

 

[NormanB]

Thanks for the info Doc. I forgot to mention that I just changed plugs. I never thought of the coils. I've had that problem on my tractor. I'll run the engine this evening when I get home and see if the problem is a coil. Thanks again.