Briggs and Stratton 21a907-0124 12hp intek motor

Old 10-25-19, 07:05 AM
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Briggs and Stratton 21a907-0124 12hp intek motor

I was recently given a snapper rear engine mower and was told it may only need its carburetor cleaned but should run. I replaced the carburetor all together with new fuel line and filter. Changed the oil and also had to buy a new battery because the mower had been sitting for sometime and it had lost charger nor would it stay charged. So I replace all the bad parts and I give it a try. All it does is act like it wants to crank but never does. The term ď turn overĒ Iím reckon thatís what it does but never will ďstart/runĒ. Iím no motor guy only know how to change oil in my truck, Iíve replaced an alternator and thermostat but all the other little slangs and names of things Iím clueless about and itís purpose. I spent days trying to research this small motor and I came across safety switches and me being a electrician i decided the heck with it Iím rewiring it from scratch without to safety switches so thatís not a cause. Still does the same thing. Only turns over. Few more days pass and I really go out of my know how zone and take the thing apart all the way to the cylinder. Soon realizing that I probably shouldnít have because when I went to put it back together I may gotten the specs wrong even tho I googled what the gaps and all. With all that said it turns over the same as before and even tho I should go in and make sure the rocker Arms are correct along with other little details rather than forgetting about will someone tell me other than the common reasons a engine wonít start what could be the problems. It gets fire. New carburetor, fuel line and filter, new wiring thatís done right (if you considered i made a mistake). Thereís a new battery, air filter. Only a acts like it wants to crank but never starts. Someone help a man with a push mower just trying to ride before the next grass cutting season. Thanks in advance
Old 10-25-19, 05:41 PM
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Did you align the timing marks on the camshaft and crankshaft when you reassembled the engine? Does it have good compression? If you give it a shot of starter fluid, does it try to start? Was the flywheel removed?

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