Gravely Compact 44" zero turn mower with kawasaki (20hp) has for several years clicked a time or two or more and then started. I assumed it was the solenoid and replace it. Starter with solenoid works on bench when 12 volts is applied;, however, it only clicks when key is turned to start with starter on the mower. I can run 12 volts from starter and it engages. My trigger wire from the key switch test 12.4 volts. What should do?