Engine Lopping

[retiredfirechief2023]

I have a JD Z335 that the engine lops when running. The governor is revving up and down. When I engage the PTO it seems to run normal! Any ideas? This surging seems to get worse as the engine heats up. I've checked the air filter, fuel filter and fuel pump. All seem to be ok. Any help would be appreciated.

 

[Auto Doc's]

The carburetor needs to be removed and properly cleaned. The air bleed system is partially blocked and not keeping a proper mixture balance, especially under load.

I have no faith in aftermarket carburetors, so, if this one needs rebuilding invest in a kit,