KAW FH500V-BS11 (17HP) on a JD LT277AWS purchased new 1999.
After about an hour of cutting grass, stopped mower for about 15 minutes.
When restarting, motor sluggishly accelerated. When engaging the blade, the motor starts losing power, laboring but did not die, disengaged the blades and returned to the shop.
Returning the next day. motor stated as normal. After cutting grass for about 15 minutes, the motor started loosing power again.
Thinking of a fuel issue, emptied the carburetor bowl, it was clean. Fuel solenoid tested fine. Cleaned air filter/ no oil in the filter.
Replaced the fuel filter, it needed it. Plugs look ok, they are 1 year old, have not replaced.
A cold motor starts and seems to run normal, but after about 15 minutes it looses power.
Suggestions of where to go from here.