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Lawn Mower Won't Start

grandspan's Avatar

Join Date: Jul 2002
Posts: 182

06-22-09, 10:56 AM   #1  
Lawn Mower Won't Start

I have a year old Troybilt mower with a Honda engine. It was used about a week and a half ago and was put away. Now it will not start. I pulled the spark plug and it wasn't really dirty or gas soaked but I installed a new one with proper gap. Air filter is clean. There appears to be a spark with the plug wire pulled and grounded to a screw driver.

It gives a backfire when you try to start it.
What I find that when we pull the start cord with the air cleaner cover off that it seems to be blowing OUT from the carb instead of having suction. I sprayed start fluid into the carb and it actually shoots flames out from the carb. If it was a car engine I would say that it either had a broken timing chain or belt.

Any advice?

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BFHFixit's Avatar
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06-22-09, 03:30 PM   #2  
Well you did not specify what engine or even whether it is a push mower or rider...assuming the prior...and it sure sounds like the shear key which in effect times your ignition to piston and valves.

indypower1's Avatar

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06-22-09, 03:34 PM   #3  
Sounds like you may have sheared the flywheel key. This happens if you hit a rock, stump, or another hard object. The sudden stop will shear the flywhhel key.

cheese's Avatar
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06-22-09, 09:50 PM   #4  
If not the flywheel key, it could also be a stuck valve or timing belt if your engine is so equipped (depending on what Honda you have).

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06-23-09, 04:17 PM   #5  
With the spark plug left in and plug wire disconnected - if you tilt the mower and try to spin the blade, do you feel compression kickback? If you do not (as you should), you may have a small screw, carbon, or ?, lodged under the intake valve. You also might have loose head bolts.

grandspan's Avatar

Join Date: Jul 2002
Posts: 182

06-24-09, 10:36 AM   #6  
Thanks for the info

Thanks for all the replies, I really appreciate it. The lawn mower was last used by the lady of the house and she assures that she shut down normally and did not hit any obstruction.

The mower is a 21" walk behind Troybuilt, 3 in 1 with a 160cc Honda OHC motor. I haven't had time to get back at it but will this weekend and check for sheared pin or woodruff type key. I'll let you know how I make out.

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