My '97 Merc. 175 EFI starts 100% of the time at the start off an outing. It will then start after being shut down most off the time, but..., occasionally will not fire at all after already running that day. Acts as if there is no spark, cranks strong but will not even attempt to fire, as if "dead man" switch has been tripped. Has happened four times in probably 20+ outings. It will always start the following day, sometimes after sitting 3 or 4 hours. Anyone run into this before? has been to the shop twice and no problem found, could not get the problem to surface for them. Help!!
