331877-0036-G1
Well this one is on my personal mower. It has problems over the years with blowing two head gaskets, losing a camshaft, and exhaust valve seat coming loose.
A couple weeks I started mowing my lawn when it start cutting out under load only. Foot tall grass but shorter grass it was fine mowing. At first I found water in the fuel filter so I thought was the cause. Well cleaned that out and mowed nearly an acre with the engine acting up. Never cleared up. So to the shop it went. After cool down pulled and cleaned the carburetor. Still the same problem. Tried new fuel pump and a clipped solenoid. Still the same problem. Pull the kill wire, no joy.
So pull the head to check the valve seat in case the staking didn't hold. It was good but the intake stem seal leaking and valves needing grinding. Upon re assembly was when I found the problem. Guess what it was? I should had found it upon my initial inspection.