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Answeredbriggs and stratton 5 hp Model # 128M05-5468-F1 will not start Help!!!!

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wayne64li
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2019/10/31 22:02:19 (permalink)
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briggs and stratton 5 hp Model # 128M05-5468-F1 will not start Help!!!!

 

Mower will not start. it did work last week. I did the following
new carb
new coil (magneto armature)
checked flywheel pin
new spark plug
mower has spark, 70 psi compression and holding. Even though the carb is new i sprayed staring fluid in carb. i also put in new gas. i took off the head. valves seem to be opening and closing. piston looks fine
Help!!!!!!!
 
AVB
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Re: briggs and stratton 5 hp Model # 128M05-5468-F1 will not start Help!!!! 2019/11/01 09:27:31 (permalink) ☼ Best Answerby wayne64li 2019/11/02 18:05:47
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Depending the engine usage have you checked the valve clearances? Could be losing most of its compression at TDC due to an overactive ARC [automatic compression release].
 
Its been awhile since I on one these but might have the new upside down throwing the ignition timing way off.
wayne64li
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Re: briggs and stratton 5 hp Model # 128M05-5468-F1 will not start Help!!!! 2019/11/02 18:09:13 (permalink)
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AVB
I found it.
I noticed that on the power stroke the exhaust valve was opening. Right there, timing is off. This mower has a plastic gear on the cam.  The gear moved on the metal shaft throwing the timing of the piston and valves out of sync. 
thanks for you help
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