i have a snapper self-propel mower. I think 19" or so. it has a briggs and stratton 6.75hp intek ohv. around a month ago i got caught in some flooding rain. ever since then it has given me problems. it used to start on the 1st or 2nd pull every time. well the day after the rain i went out to cut and it wouldnt start so i put a new plug, changed oil, drained fuel. it cranked after around 5 pulls. plug was all black. a week later threw in another plug. it has slowly been losing power. well this week it went to total crap. it would barely stay on after i got it cranked. (which was work). even it short grass it would really bog down. even the self propel slowed down. my friend over the phone said it was probably the magneto. Does that sound correct? If so I find it by following the spark plug wire? What does it look like? He said it probably has rust on it. Do i clean it with sandpaper or should i just replace it. Ive never done this before. It also started blowing black smoke out the muffler. after i throw some oil in it it blows white. It started burning oil or something. Also in one day the self-propel cable broke and I just pushed it to finish. Next yard the string to start it broke. Just my luck.