Tractor will run at operating speed for a while, RPM begins to decrease almost to stall. I stop, take it out of cutting mode, RPM returns to idle. I can continue to operate for a while only to have it reoccur.
Noticed that the fuel filter empties and appears not to have gas flowing through it. If I gently slap it 6-10 times it begins to refill by about a third its volume.
Replaced gas cap, fuel filter and fuel pump with no remedy.