I've had this motor since new, but with the fishing I do, put most of my hours on my electric trolling motor. My 97 Johnson 70 hp has only 50 hours on it and has been well taken care of...and has worked great. This year, however, after running it for several days on a trip, I can not get it to start. It has new plugs (per the manual) and it turns over fine but won't fire. After a few minutes, I smell and see gas (indicating flooding), but I can't figure out why. Any suggestions?