90hp 4stroke on 170cc?

[Deltaviller]

That makes sense. The marine world seems to have inherited a lot of little rules from bygone days and they generally seem to be enforced. Many of the rules, which I'm currently reviewing, seem well founded and vital, like the navigational rule about "giving way" to a boat in the 12 oclock to 4 oclock quadrant. A few of them seem a little nit-picky, like specifying the exact size of various placards that must appear onboard vessels greater than 39.4 feet in length. Also, one of the worst crimes appears to be use of obscene language on a VHF radio, punishable by a fine of $10,000, imprisonment of 2 years or both. Thats a federal law per the "Federal Requirements and Safety Tips for Recreational Boats" pamphlet.

[suitekids]

Hello there MSANDEL, It's quite confusing, The 4 stroke Yamaha's 75 & 90 are identical in all respects except the computer and the air intake tube, but 20% horsepower increase is better ofcourse if you are considering a four stroke in the Yammi midsize configuration, both weigh in at a hefty 369 lbs. Obviously there must be one manufacturer of a 90 hp motor on the market somewhere that exceeds the the 388 lb transom limit, so I'm going to assume they negate all 90 and up motors from the 170 series from being used. I don't think Triumph cheapened the transom from the 90 hp rated ones, But maybe there is a horsepower to weight ratio going on. It seems difficult to get a real definitive answer. A 90hp 4 stroke on a 170cc swinging a 13 1/2 x 20 inch pitch runs at 52 mph WOT, That's more than fast enough for any boat on the water these days, And as Dick had mentioned the only things in the water are the cavitation plate on the motor and about 2 inches of boat, What it does for us lighter guys (pokin' fun at Dick!!!) is, it's out of the water and on plane in about 3 seconds or so, and you can run in and out of bigger surf at the inlets to " ride on the swells" or get out of the way really quickly!! and you can stay on plane at lower rpm swing the bigger prop, fuel is about the same, run all day and into the night with a tank full, and very quiet and reliable, the wind is louder than the motor at speed. Hope this helps with some of the confusion, IMHO.........Dan