ZTS 6000 usually won't start. Some days it cranks right up. When the engine turns over the engine starts. On the days it will not start the starter will not turn over engine although it tries to turn over engine. I only try 2 for 3 times because the starter and wires get hot on these "no start" days. Already burned up one starter. Starter, solenoid, and battery are all new and battery is fully charged. The engine always turns over easily with the spark plug out. I thought there might be a compression release valve incorporated in the engine for starting but have not found one. Any recommendations would be appreciated. Thanks...