My Yard Machine MTD Mower Model 670 Won't Start

Dead Battery

• A dead battery on your Yard Machine will prevent a start. The Yard Machine 670 uses a 12-volt battery to assist in cranking the engine. If the battery is out of warranty or has exceeded its lifespan, chances are you have dead cells that won’t keep a charge. The battery indicator on the dashboard can let you know if your battery is dying. If you have a wet cell battery, you can check the cells yourself for liquid levels. Otherwise, have the battery tested at an automotive center for charge capacity.

Battery Connections

• Check the battery connections to ensure they aren’t damaged or in the wrong place. The positive wire is red and indicated with a “plus” sign, while the negative or ground wire is black with the “negative” sign. Ensure they are connected to the right posts on the battery. Check the terminals and post for any corrosion, which can be cleaned with a stiff wire brush and baking soda. Corrosion can interfere with the battery charge.

Safety Interlock

• The Yard Machine 670 has a Safety Interlock system in place before you can even attempt a start. The Lift Lever, located on the right side of the dashboard, must be in the “off” position so that the mowing blade is not already engaged and out prior to start. There is also a safety switch underneath your Yard Machine’s seat. If no one is on the mower seat to engage the switch, it won’t start.

Starting Position

• If the Safety Interlock system is in place, ensure that your Yard Machine is configured to start. Anything out of configuration will prevent the engine from starting or turning over. The clutch must be depressed to set the parking brake. The Yard Machine 670 also makes use of an ignition key, so ensure its in and turned to the “start” position. If you use the choke to start your engine, turn the choke knob off to prevent excess fuel flow. Excess fuel could flood the engine and cause it to stall or stop.

Fuel and Fuel Flow

• Fuel could be another issue if your Yard Machine won't start. Check the tank to see if it's full or at least a third full. You need enough fuel to reach the primer, which sends it to the carburetor. If your Yard Man is on a slope, a partially full gas tank will send the gas to the back, preventing it from reaching the primer. A clogged fuel filter or fuel lines from dirty fuel can also impede the fuel flow.