Self-propelled lawn mowers experience many of the same common problems as regular push mowers. Self-propelled mowers may also present various problems individual to this type of mower because of the added gears, cables and transmission to work the self-propelling feature of the mower.
Look at the hooks at the ends of the cables, which can detach from the transmission or the handle, causing the self-propelled function not to work. Examine the cable for wear because tension will wear out the cable over time; change the rubber cable housing if frayed to ensure the wire inside stays protected. If the cable becomes stretched or warped, it can cause the transmission not to engage properly; replace the cable if this occurs.
If the transmission is slow, slipping or fails to engage, examine the cable first. If the cable is fine, remove the transmission cover and look for debris, packed grass, dirt, wood chips or gravel in the transmission. If the transmission is free of debris, lubricate the transmission; transmissions need regular maintenance to remain properly functioning.
Examine the gears for debris that can cause them to slip or stop. If the gears are slipping, look at the drive chain to see if it has come loose; if there is any play or movement in the drive chain, it is loose and requires tightening. If the chain is tight, look for debris such as packed grass, dirt or debris in the gears, and clean them out if necessary. If the gears move stiffly, lubricate them using a regular maintenance schedule, which is especially important for the gears attached to the drive wheels.
If the mower is moving slow, examine the height of the blade and the grass; high or thick grass slows down a lawn mower. Look at the drive belt, which sometimes becomes loose or detached. If this is the case, reinstall the belt and adjust the drive control. If the belt is damaged or broken, replace the belt.
The Slope of the Land
Self-propelled lawn mowers are more difficult to operate moving uphill on a slope. This type of mower is best used running downhill or sideways with the slope because the drive gear and wheels are usually on the front wheels. Mowing uphill requires the mower to work harder and can cause faster wear on the transmission and related parts.