08 729G2 Kubota Gas, won't stay running right

[TAS_TODD]

Gents...I'm scratching my head here. My 729G2 Kubota Gas mower will not stay running right. I can start it and run it up, but once I engage the PTO, it'll start falling on it's face and start to spit and sputter. I'll turn PTO off, and it'll recover. It will sometimes catch up with the PTO on, but once I start trying to cut, it'll start missing, and popping again.

In-line filter has been changed last year. It sounds like a fuel starvation issue. Has anyone else experienced this problem. I don't want to start troubleshooting by parts replacement. As of now, I'm leaning towards replacing the fuel filter again, then the fuel pump. Ideas?

 

[Rivets]

I know that this may sound stupid, but the first thing I would check is the PTO drive to make sure nothing is overloading it bogging the engine down. Need to look at all parts, making sure everything is free. One thing you could try is to remove the PTO belt and then engage the PTO. Trying to figure if it an engine or PTO problem.

 

[TAS_TODD]

Let me add...Even without the PTO engaged, at full throttle, it'll stumble also. If I pull the throttle back a little, it'll catch up and run fine. Even driving it around w/ out the PTO, sometimes it'll stumble.

 

[Rivets]

Ok, that means you may be correct that it may be a fuel problem. I would check a few things before throwing parts at it. First check for debris in the fuel tank which may be blocking the pick. Second I would check the fuel pump output. To do this I would remove the fuel line at the carb and pump fuel in a clean glass jar. You want to pump out between a pint to a quart. You should see a steady flow with no air bubbles. Will probably need an assistant to turn the engine over while you watch the fuel flow. Then look at the fuel in the jar. look To see if you have any separation in the fuel at the bottom of the jar. Cover the jar and give it a five second shake, when you stop the fuel should look clear with no bubbles. Bubbles are cloudiness indicate water in the system. If all these indicate the fuel is good and flowing properly, then I would swap out the fuel filter. If you can find a clear one I would use that so I could watch the fuel flow.

 

[bertsmobile1]

Run the engine for a couple of minutes then turn it off & pull the dip stick out
If you see smoke rising then you have a blown head gasket

 

[Renchy]

Had just about the same issues, PTO would work but engine would sputter than die as it got hotter. Thought fuel filter, fuel pump but nothing worked until I looked at the distributor and found that the electronic ignition module was shorting out. Replaced module haven't had a problem since.
2004 GH 725G2, bought used from local high school.