I have a Briggs & Stratton Model 98902 Type 2098 lawn mower (inherited from sister) that I cannot get to start.. Where should I start with troubleshooting... I replaced both the air filter (that didnt look that bad) and the spark plug (which was pretty fouled) and yet it still wouldnt start. I currently have the motor completely torn down, cylinder wall and head looks fine (some carbon build up). The combustion chamber is pretty built up with carbon and the intake valve had quite a bit of build up (not the exhaust though). Is there anything besides cleaning these parts that I should do??? Especially since I have it completely apart??? All the internal components show no sign of wear, I forgot to check for spark, but I know that when I tore it down, the plug smelled of fuel... Possibly the ignition coil??? What do you guys think???