MTD Pro Turf Riding Lawn Mower Won't Start - TROUBLESHOOTING

Old 04-17-15, 07:08 AM
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Question MTD Pro Turf Riding Lawn Mower Won't Start - TROUBLESHOOTING

My lawn mower won't start. Not sure what the issue is. It was working fine until I was mowing the yard down a steep hill and it stalled. It won't start now. Gas was full and was new fresh gas for spring. The battery is new. I replaced the fuel filter, air filter, and spark plugs thinking that may help...but it didn't. Choke throttles back and forth fine too. Any clue what might be the issue?

You can watch video below to hear how the engine sounds when trying to start it.
Old 04-17-15, 07:53 AM
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Boy, I'm not hearing a good "pug, pug, pug" sound that engine has compression. Before going down that route though I'd try some simple tests first.

Try putting a teaspoon of gas deep in the throat of the carburetor and try starting it and see if it fires or sputters. If you can't get the gas up into the carb, remove the spark plug a put a teaspoon directly into the cylinder, re-install the spark plug and try starting it. If with either method you do get it to sputter or fire a few times then it points towards a fuel problem.

If the engine didn't sputter or fire with the gas test remove the spark plug and attach the spark plug wire to it. Position the spark plug so the tip or threads are touching bare metal of the engine and turn the engine over. Look for the spark plug to spark. If you don't see a spark it could be a bad plug, bad spark plug wire, bad ignition coil, shorted kill wire or bad ignition switch among other things.

If you had spark and still the engine won't fire then I'd pull off the valve cover and look at the valves. Do both move up and down when you turn the engine over? Also look online for the procedure to adjust the valves as long as you have the cover off.
Old 04-17-15, 10:43 AM
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I agree about it not having sufficient compression. I think the engine is blown (Tecumseh engines are famous for coming apart inside) or a valve is stuck open, something like that. Since it happened on a hill, I lean towards the engine being blown, since when on a hill all the oil is to one side of the engine. If the engine is low on oil, it will lose lubrication on a hill.

Is your oil level low?

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