Small Engines (Lawn Mowers, etc.): problem starting a B&S riding mower, briggs and stratton, bolts and nuts

Question
I purchased a 2 year old  mower like new, with a 17.5 hp Briggs and Stratton. The problem is when I go to start it , it will only spin 1/2 a turn and recoil back. The battery is new and fully charged. It isn't flooded, as when I pull the plug , it spins as normal.I asked the B&S site , but they just said go to a dealer, which is 70 miles away for me. I suspect the anti-backfire solenoid? Would it stop gas and air from entering the motor and turning if defective? If I keep hitting the key it will eventually turn over and start in 1 spin.
Thanks in advance for any help.
Larry

Answer
Larry, sorry you didn't like the answer.  Kick Back is caused by the engine being out of time.. The other think that would explain this is valve settings or an internal electrical issue.  I mean the coils.  

The anti backfire feature is a needle that is pushed into the nozzle when the ignition is turned off.  

If you pull the plug and it turns over fine you are relieving the compression in the cylinder just as an exhaust valve does. I would check valve clearance and maybe a plugged muffler.




You are saying that the engine starts and then kicks back. Your engine is out of time.  Either the flywheel key is sheared or the internal timing is off.  Remove the flywheel and check the key.  Replace if sheared or partially sheared.  If not drain the oil and open up the engine.  This means to separate the engine at the crankcase gasket.  Look at the crankshaft gear and the camshaft gear.  they have small marks on them where they align.  If out of time retime the engine by aligning the marks exactly. Be sure to put in a new gasket when reassembling. As long as you have the engine off replace the oil seals too.  Don't forget to torque all bolts and nuts.