Small Engines (Lawn Mowers, etc.): Starter/clicking noise

Question
Hi Eric-

Bought a used riding lawn mower a few weekends ago. Has a 8hp B&S vertical shaft with both recoil and electric start. Got it running with the recoil start but having troubles with the electric start. Installed a garden tractor size battery (few years old but was on the charger for several hours)and when turning the key I would hear a loud click by where the positive cable goes into a black box and then comes out and goes to the starter. Tried several times and would just click. Thinking that the battery might be weak I pulled the full sized battery out of my old car and hooked it up. Engine started right away. Shut it off and tried again. Click, click, click from that black box. The car battery starts the car fine so I think that has a full charge. Bad starter or something else?

Thanks,
Jim

Answer
The click is coming from the starter solenoid, the black box.  Low voltage, bad battery, is the most common cause.

If the mower starts using another battery then the mower starter is not the problem.

I would have the battery load tested at you local auto parts store.

Make sure the battery has been on the charger before taking it to get it checked.

Also, when connecting the battery, clean both the battery terminals and cable ends with a wirebrush before connecting the battery.  I have fixed a lot of clicking problems just by cleaning the connections.

Eric