Sound analysis/advice so far.

I didn't see anyone mention that it could also be a pinhole air leak in the fuel line or fitting.

If you have a manual choke, see if it will run half-choked, this can increase suction to the fuel supply, and overwhelm some obstructions in the carburetor. A palm over the air intake can provide this choking behavior too.

I've had luck shooting some starter fluid (ether) directly into the carb to clear out most gunk and varnish.
I'd give it a try before ripping deeper into it.

Blocked jet, stuck float, most likely.

take the cap off of the gas can (probably not the issue because it hasn't run long enough to create a vacuum if the vent is clogged), check the fuel lines and see if any of those are mushy or could be bent shut. Easiest thing would be to hook a hose to the fuel pump input and into a gas can and buypass everything leading to the carb entirely. Also try tapping hard on the side of the carberator with the plastic handle of a screwdriver, it might have a stuck needle or something in it. Can also put your hand over the air intake right after it fires and sometimes the big vacuum increase will dislodge anything in the carb. Could also be a bad air filter or stuck choke.

Since you run ethanol gas you’re probably going to need to take the carb off and clean it.

I have a Kubota with the Kawasaki 21.5hp twin. I put regular pump gas and ethanol treatment in it. Change the 30w oil and fuel filter in it regularly.
Had it about 5-6 years or so; mine was having the same symptoms- it would fire and run with starter fluid until it burned that up. I replaced the fuel pump and carburetor (whole thing)- runs like new. Spent about 65 bucks or so on both on Amazon. The carb kit was gonna be about 30, so 50ish for a new one made sense.

I removed and opened up the carburetor....damn thing is as clean as a whistle. Bench tested the fuel shutoff...works good. I put everything back together, same problem...starts and shuts off.

I took my hat off, scratched my head and started focusing on the fuel shutoff. Turns out, the solenoid is energized in the start mode but not the run mode. Problem indentified, now I need to know how to fix it. What supplies voltage to the solenoid in the run mode?

^^^^^Check the ignition switch itself and any relay(s) between. Also make sure it’s full of oil.

This message has been edited. Last edited by: PowerSurge, March 18, 2020 04:54 PM

I ran into this last year. Tried spraying ethanol around lines and mounts just to see if it would pick up and nothing.

turns out the ethanol eats the diaphragms in the carburetor you need to rebuild it. It's a inexpensive kit and doesn't take very long to do. Mine started right up and ran fine afterwards.

Replace carb and it will be fixed. Regular gas gums up the inside of the carb it is cheaper and easier to replace the carb then fight the mower.

Dean

quote:

Originally posted by dfwglockguy:
Check your oil level. A lot of engines have a low oil level/low oil pressure sensor. If you have normal oil quantity the sensor might be bad.
Good luck

Check this first. Unplug the sensor and see if that solves it.

you did read the original post that he has already done that...

I ran a jumper wire to the solenoid and mowed my yard. That bought me some time...now I have a couple of weeks to figure it out. Thanks to everybody for their input.

quote:

Originally posted by P229 357SIG Man:
I ran a jumper wire to the solenoid and mowed my yard. That bought me some time...now I have a couple of weeks to figure it out. Thanks to everybody for their input.

The key switch (or stop switch), is there some sort of safety sensor/switch in case you fall off that shuts it down, if so check that. Some engine safety switches such as oil pressure, overheat, are normally open when the mower is off, and then closed when it is running, try jumpering the wires on those 1 at a time. Call your local dealer and ask them and they might have a better idea of what fails on your mower.

Check if you have a seat switch. If so, the switch or wiring may be faulty. You can jumper the connector at the switch to verify.

It sounds like you have a loose connection through the ignition switch. Either that or there is a seperate relay for the start and run circuts.