Z655 mower intermittently bogs, looses power, requires choke to run????

[Jimbo45]

My 14 year old son started a small mowing biz this summer (20 properties), and we bought a Z655 24 HP Kawasaki, zero turn, used, with 250 hours. It normally runs good, and is a clean mower. He mows about 2-4 hours at a time, and about other every time he mows, he will bring it home with this problem. He will mow, and it will loose power, and die, and the only way to restart it is to choke it and run it on choke for a bit, and it will drive without the blades going, but when he hits the PTO again, it looses power again and dies. After letting it sit a few hours the problem goes away for a while. Some days it does this, and some times he can mow 4 hours straight with no issues. He thinks it might happen more often when its hotter out, or when putting a bigger load (tall grass) on the mower.

I'm betting its a fuel delivery issue, I've checked the gas cap for a vacuum when this happens (nope), the fuel filter, and briefly the fuel pickup in the tank for splits or leaking around the top. I have also removed the carb and cleaned it twice very thoroughly, with jet probes and cleaner, and never find obstructions. I am so tired of this mower at this point. I think I will order a new fuel pickup, new fuel lines, filter, and fuel pump, and see what we come up with. Any suggestions?

 

[bertsmobile1]

Two sides to this
Not enough fuel / too much air

Usually you get surging when one or the other of the above happens.
Check the valve lash
Check the battery voltage, engine off, engine on blades off , engine on blades on
Also check each cylinder by pulling the plugs on each side one at a time - the engine should run roughly the same on either cylinder.

 

[Jimbo45]

Two sides to this
Not enough fuel / too much air

Usually you get surging when one or the other of the above happens.
Check the valve lash
Check the battery voltage, engine off, engine on blades off , engine on blades on
Also check each cylinder by pulling the plugs on each side one at a time - the engine should run roughly the same on either cylinder.

Will do. I did have to replace the voltage regulator on this mower when we first got it. After replacing it, all voltages were on par. It does seem to be a fuel delivery issue, as it is so intermittent, and dies out completely and won't run without choke when this happens. Then, the next day it will fun fine. I do need to check the valve lash though, good call. I just ordered a new fuel pickup, fuel filter, fuel pump, just now, and will get new fuel lines locally. Hoping all that will fix the issue.