Hello, does anyone know what the min. or max. hp outboard will work on my 1976 20' cruiser center consoul boat? The max. plate on the boat is missing. I have a 85hp and a150hp, just wondering if the 150 was too much. Thanks, Jim
whats the width at the widest point ontop the rails?
general formula for Horsepower rating is
Length (feet) X width (feet) X 2 then subtract 90 and round up to the nearest 5hp increment.
Lets say yours is 7foot wide, that would be 20x7x2 = 280 then -90 = 190hp
This is a formula of a bout builders site and the ratings seem to be on the high side of what most manufactures recommend but they usually play it safe. My boat is 75hp on the plate and 100hp by that equation. My friends 21.5' is 150hp on the plate 190hp by the equation. I really don't think you would be happy with the 85hp engine on a 20' boat even if it is light, my friends 21.5' is a bare bones lightwieght aluminum center console and with a 110 V4 rude' on the back it gets pretty sluggish with 4-5 people on board
Minimum: 80% of the result from the formula described above (length x width x 2 less 90) - it's just a rule of thumb, but I have no doubt you'd be dissatisfied with any less than that.
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