B.E. Nelli,
ImVho, the BEST way to find a nice 25HP or any other vintage OB is post a 3x5" "WANT TO BUY" ad on every neighborhood grocery store & "community" bulletin board AND a "WTB" to your local craigslist.
Over the last 4-5 years, I've bought at least 2 DOZEN in exactly that way & paid no more than 250.oo for any of them.
(My latest "treasure" is a 1958 Electric Start, 18HP Johnson, that needs NOTHING but a "good bath", new plugs, points, condensers, coils, a carb kit & a water-pump impeller.)
For 250.oo or LESS, it's hard to find a better deal in an OB motor, than that.
(My BEST "As Found Treasure" was a 1965 Johnson "long-foot" ES 35HP with less than 25 TOTAL hours from an estate sale, for 225.oo, that needed NOTHING except an impeller & clean fuel.)
yours, satx