It is common to only have one motor on when idling through the marina or somewhere when a no wake zone is present, at least that's what I have always done. Gas is expensive for those merc 500s so any saved is a bonus. The best thing about 2 motors is one in forward and one in reverse...killer donuts
Over time the small difference of tending to turn one engine on before the other adds up. Or one engine will die on your way somewhere and it wil add up some extra hours on the other engine. Thats not that big of a difference for a boat though, tim
RE: How is it possible that one motor has less hours on it than the other?
I have twin engines on my boat and the hobbs meters have a difference of about 50 hours. It just turns out that way over a period of time. While manuvering in a marina I keep them both running for steering purposes but I sometimes shut one off while trolling. Keeping the right engine running while fishing keeps the battery charged so the bait tank pump doesn't drain it. The left engine is isolated from that power system so it's the left one that gets shut off and see's less hours.
"I know it all, but I can't remember most of it..."