after engine gets hot, will not restart. when it finally does start, runs on one cylinder, then finally runs on two. acts like it vapor locking or flooding. blows a little black smoke, then clears out and will run for 10-15 minutes, then loses power and wont cut grass. i beleive the ign. mod. is breaking down after it gets hot? do i have to pull engine to replace module. Thanks for any info cdo