I am still using a 1967 Evinrude 5 HP outboard that I purchased new. Anyone else using an outboard of 40 years or greater age? Honestly, I use this moter regularly and it runs like a top. I run all gas out every time I use it and treat gas.
Can't beat it but I can almost come close to matching it.
I've got a 1970 Merc 9.8 that my dad bought brand new the week before I was born. I don't use it regularly, but I do run it at least twice a year and change the impeller every 2 years just to keep the thing going. My regular motor is a 1979, 20hp Merc I run crabbing every spring, summer & fall and duck hunt with every winter. It was re-ringed 5 years ago and has more hours on her than a $2 whore.
Both of 'em start right up and run like tops. If you take care of your outboards, they will last forever, and it don't matter who made it.