John Deere 757 zero turn - Ignition Problem identified.

[txgp17]

The mower:
John Deere 757, 25 HP Kawasaki, 60" deck, 800-ish hours. Serial # TC0757B062XXX
The problem:
The engine fires and runs, but when you put it under a load, it's like the mower is starving for fuel. Engaging the PTO almost kills the engine, and it won't get up to full engine speed with the PTO engaged. Also, if you try to mow a hill leaning to the left, the mower almost dies. If the mower is tilted to the right while mowing, it does OK.

I've had this mower for a few years, and it's away ran great. It's stored outside, under a cover. A few weeks ago, my wife was about to mow and found the cover removed, with the fuel cap off, and the fuel tank empty. We suspect someone came in the yard a stole the gas out of it. My solution was to completely drain the tank with a vacuum fluid transfer pump, and then refill it with fuel. I only run non-ethanol. And my fuel is always stored indoors. After refilling the tank, and fired the mower up, we noticed the low power issue. I replaced the fuel filter and the fuel pump with OEM parts. I also blew some compressed air backward through the fuel hose going to the tank, to make sure there wasn't an obstruction, but the problem still exists.

I'm at a loss, and don't know what to do next. Thanks in advance for any help you guys have for me.

 

[ILENGINE]

Maybe unrelated but make sure that you have spark at both spark plugs. A misfire on non firing cylinder can cause similar symptoms.

 

[Bertrrr]

check your fuel pump , might be some debris in the valves stopping it from operating like it should , there are 2 small check valves and most are not repairable.

 

[txgp17]

check your fuel pump , might be some debris in the valves stopping it from operating like it should , there are 2 small check valves and most are not repairable.

That was the first thing I tried. Replaced the fuel pump and filter with OEM parts. No change.

check your fuel pump , might be some debris in the valves stopping it from operating like it should , there are 2 small check valves and most are not repairable.

Whelp, turns out I have an ignition problem, not a fuel problem. Dad taught me "Fire, Fuel, Compression" when diagnosing things. Because the problem showed up at the same time someone tampered with the fuel tank, I automatically assumed it was fuel related.

With the engine running, pulling the plug wire on the right side results in no change in engine RPM. Pulling the left plug kills the engine. So, I bought an OEM replacement ignition coil, installed it, and gapped it. While buttoning everything up, I disconnected a wire on the right-hand side of the engine, it fell apart, and the insides were totally corroded and degraded. So now I've got to get those replaced.