When faced with a lawn mower that will not start, one easy way to narrow the pool of potential causes is to work through common malfunctions. Hayter lawn mowers, like all lawn mowers, have a few maintenance issues that, left unchecked, can lead to a malfunctioning mower. Working through common problems cannot only help you solve your problem, but can take care of seasonal maintenance and ensure your mower is functioning properly once the problem is fixed.
Prop the lawn mower up on blocks and check the underside near the blade for accumulated grass clippings and other debris. Over time, grass or bits of string can sufficiently bind up the blade to prevent the mower's engine from getting started. Cover the engine with a plastic trash bag and secure the bag with a bungee cord. Use your garden hose to spray the underside of your mower clean and allow the mower to dry before removing the bag and attempting to start.
Spark Plug Issues
Remove the spark plug from the engine and examine it for signs of fouling. Fouling is the accumulation of rust, minerals or carbon on the end of the plug that fits to the engine. Over time, fouling can lead to a malfunctioning plug that will fail to ignite the mower's fuel and turn the engine over. Hayter recommends changing the spark plug every 100 hours or once seasonally. Replace the plug and attempt to start the mower.
Hayter recommends keeping the intake manifold clean and clear. The intake manifold is responsible for providing the engine with air to combust with gasoline. It is a small metal port typically located on the side of the mower, with a filter attached to the end. This filter can become clogged with grass clippings and other plant debris and deprive the engine of oxygen. Remove the filter and clean or replace as necessary. Reinstall the filter and attempt to start the mower.
Exhaust and Exhaust Guard
Hayter indicates that your mower's exhaust and exhaust guard should be kept free from debris and periodically cleaned. Allow your mower to cool if it was running prior to encountering the starting problem. Brush clean the exhaust and exhaust cover and ensure that no grass or leaf litter are trapped in the exhaust manifold. Attempt to start the mower once more.