That is one of those frustrating things with an engine. What happens if you pull the choke out a bit? If that helps then the carb is "dirty"and needs to be cleaned out. Then I would start with checking the valve lash. Check all electrical connections at the engine. If you have a ground wire take it off and wire brush the connection on the mower and wire. There a many things to check so you will have to try one thing at a time. I'm thinking it is a carb issue or maybe just maybe electrical. How many hours on the engine?

 

I sure hope it isn't electrical. I'll try what you suggested with the choke and see if it clears up. If not i'll pull the carb and see what's going on. The engine has around 75 hours on it. I appreciate the advice.

 

I had a lot of governor hunting and light surging on my FX100V and well as all of my Honda GX390's all under no load. Switching to non-ethanol fuel has taken care of this issue with all my equipment, I also need to use the choke way less as well.

 

I'll keep that in mind. I already run non ethanol fuel in all of my 2 stroke equipment. I have had far less issues with my saws and trimmers since I made the switch. My other mower always ran fine with regular gas, so I didn't really think about trying that with this mower.

 

Hard to diagnose with a video but it sounds like a lean condition and one I suspect is water in the float bowl if this is carbureted. I have seen this many times where water sits in the bottom of the bowl because it is heavier than gasoline, and starves the engine for fuel. One tactic that has worked for me to clear a few issues is shut the fuel valve off and let it run out of fuel. This allows the float needle to fully open and clear anything there, and can help clear water in a bowl.

It also sort of sounds like an ignition issue. You might have to make that call in the field but many times coil issues get worse with heat. They may start fine, then develop an issue. As well, throttle position can be telling whether fuel or ignition.

This does not sound like a fuel filter. Usually demand of the engine shows the true colors of lack of fuel delivery.

 

Hard to diagnose with a video but it sounds like a lean condition and one I suspect is water in the float bowl if this is carbureted. I have seen this many times where water sits in the bottom of the bowl because it is heavier than gasoline, and starves the engine for fuel. One tactic that has worked for me to clear a few issues is shut the fuel valve off and let it run out of fuel. This allows the float needle to fully open and clear anything there, and can help clear water in a bowl.

It also sort of sounds like an ignition issue. You might have to make that call in the field but many times coil issues get worse with heat. They may start fine, then develop an issue. As well, throttle position can be telling whether fuel or ignition.

This does not sound like a fuel filter. Usually demand of the engine shows the true colors of lack of fuel delivery.

I agree. I forgot about that. Water in the fuel does strange things.