Small Engine Troubleshooting Problems? Ask a Mechanic Now.
Hello. My name is***** will be happy to assist you. How old is your mower?
If your mower will pull up hills for 10 minutes, but fails after 10 minutes of use, it is very likely that you have some internal problems with your transmission.
Check to see if you have any obvious oil leaks on your transmission.
Make sure that the bypass lever on your transmission is fully releasing. If your oil is contaminated, or if your oil level is low, this can cause our problem. If your transmission pulley, or the pulley that bolts to the bottom of your engine, is worn, this can cause your drive belt to slip, although your belt is new.
I would inspect the inner running surfaces on your transmission pulley, and your engine pulley, for wear. If these pulleys are worn, your belt will run deeper into these pulleys, causing a looser fit.
We can continue from here. Thanks!