How to Troubleshoot the John Deere STS 38

Check the battery cables and battery. Failure to start may simply be a poor connection to the battery. Tighten if the connection is loose. If the mower has not been used in a while, the battery may have lost its charge and need to be jumped.

Check the spark plug. Replace if the engine is not starting. It is a good idea to change spark plugs every season.

Check the fuel filter. Look for debris or clogs. Replace, if necessary. If the filter is clogged, fuel struggles to get through and robs the engine of performance and may even fail to start.

Perform an oil change. Drain all the oil in the engine and replace it with new oil. Replace old gas with new gas. If the mower is just coming out of storage, consider using a spring fuel additive. This helps clean the proverbial cobwebs from the engine.

Check the intake and air filter. The intake is where air comes into the engine. Look for clogs or debris and remove it. The air filter helps clean air that goes into the engine. Over time, the air filter can become clogged. Replace it and performance should increase. A completely clogged air filter can keep the mower from starting.