Re: 1957 evinrude 7.5hp
Tracker--Ditto Scott...for example, there's a '57 Johnson 7.5 on ebay asking $600! There's an outfit on ebay that's set a reserve of $300-400 on the mid fifties 5.5 to 10 hp range. Then there's free ones sitting in garages, though I've yet to find one. So, essentially it's worth what anyone will pay. But here's the key--although you may find a far more efficient newer motor (for about $1200-1500), you may not find a hardier, quieter, nicer running outboard in that hp range. If it were mine, I'd fix it, unless it's well beyond repair, or find someone who would care for it, because then it will outlast all of us, and its value will be in its age, and not dollars.