Years ago, when I was looking for a 100HP it was a tough one to find. In fact, I never found a used one I was willing to buy and instead bought a new/used boat.
For outboard sans boat, I would say CL or eBay are your better bets. But in my case, I would have more likely found one a few hours from me as opposed to locally. The other place I tried was local marine repair shops. Most of 'em had something smaller or bigger than what I wanted but nothing in the 100HP zone.
