I have a Jogn Deere L110 the engine surges (revs up then down, up and then down) repeatedly while mowing then smooths out only to start surging again. That was last week. Yesterday after 15 minutes of mowing it surged then quit running and would not restart. Today it started only to surge and die with in a couple minutes. It is low on gas but at a level where it normally ran fine.

Hi,
Something is restricting fuel flow like a clogged filter, bad fuel pump or pinched fuel line. Early models had a fuel line that could be pinched at the very rear center of the frame by the tank and frame. Later models moved the line to the left top of the tank under the seat platform where it could become disconnected.
Peace,
Clarke

Hi,
Something is restricting fuel flow like a clogged filter, bad fuel pump or pinched fuel line. Early models had a fuel line that could be pinched at the very rear center of the frame by the tank and frame. Later models moved the line to the left top of the tank under the seat platform where it could become disconnected.
Peace,
Clarke

I recently noticed that I could crank the engine standing next to the mower (while off the seat). I always thought I needed to be on the seat as was part of the safety feature. Is this a bad seat switch? Could a bad seat switch also cause the reving problem and stopping the engine while I'm on the seat?

Hi,
If the brake was locked in park, it is possible to crank it this way. Generally a bad seat switch would not cause a surge though it could cause the shutdown. There are two wiring harnesses on that model. What is called the rear harness had some problems with broken and bare wires on some earlier models. The part #GY20168.
Peace,
Clarke