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Hey all, I have a 1977 B28 with Mercruiser 260hp motors and a hard top. My current prop size is 17x16 and the boat runs with in the engine specs. I run my boat at 2800-3000rpms and very rarely above 3000rpms. My cruise with full fuel and gear is around 18kts. I was throwing the idea around to have my props tweaked over the off season to get a better speed at cruising RPMs. Should I go with a cup? or pitch change, or just stay with whats working? Thank you

I have a 1985 28 w/ Merc 260's. Original w/ 1550 hours. I went down an inch to 17x16 when I bought the boat to get up to 4400, which is at or near the top of the RPM spec. My boat holds 240 gallons. When It's full, I get 18.5-19 knots at 3000 RPM's. Normal load, a little over 20. I don't think I'd go up in pitch. If the extra cup could help a little, I don't see why not, but it may not be worth the trouble. If you give it a try, I'd be interested in hearing the result. Leigh

Cup is the way to go, but talk with the prop shop. They may need to tweek the pitch a little so you don't overload the engine.

I have a 1977 28 Moppie with the 260 hp Mercruisers. The props are 17x17 and engines turnup 4200 as advertised.