Small Engines (Lawn Mowers, etc.): briggs and stratton engine

Question
hi, i have a briggs and stratton engine model 287707 type 0224-01 on an mtd riding mower. (14.5hp ohv). i cannot get the engine to run, i adjusted the valves (correctly), i bought a new battery, i checked the fuel (smells and looks fresh). fuel is getting into the carb. when i try to start the mower it cranks HARD. i take out the spark plug and bam quick spinning. i even loosened the valves at one point just to see if it would spin fast with the plug in and it would not. im at a lose right now with how to figure this out.

Answer
Sounds like a definite valve adjustment issue, or the internal compression release. Loosening the valves will only make the issue worse, for the exhaust valve must be adjusted correctly to allow the compression release system to work due to the fact it allows the exhaust valve to to stay open a bit at starting to lower the cylinders starting compression. Are you sure when you adjusted the valves to factory specs you were directly on top dead center of the compression stroke, or perhaps 180 off on the exhaust stroke?..........Tom