Volvo Penta DPS Prop Question

[pnwman]

I've got a 28 foot Bayliner that had the Volvo Penta 350 with a 290 DuoProp. I recently had to repower it and took the Volvo Penta 5.7Gi engine and DP-SM outdrive (1.95 gear ratio) out of a 20 foot cabin cruiser. The new setup came with D7 props, but I can't get the boat to go above 3000 RPMs. I had tested the engine in the old boat, but never pushed it above 3000 because we were going over 30MPH at that point. At 3000 RPMs in the 28 foot Bayliner, we are only doing 14MPH. Should I drop down to a D3 or possibly a D2 prop set? Also, should I look at switching to the I series of props?

 

[4now04]

I've got a 28 foot Bayliner that had the Volvo Penta 350 with a 290 DuoProp. I recently had to repower it and took the Volvo Penta 5.7Gi engine and DP-SM outdrive (1.95 gear ratio) out of a 20 foot cabin cruiser. The new setup came with D7 props, but I can't get the boat to go above 3000 RPMs. I had tested the engine in the old boat, but never pushed it above 3000 because we were going over 30MPH at that point. At 3000 RPMs in the 28 foot Bayliner, we are only doing 14MPH. Should I drop down to a D3 or possibly a D2 prop set? Also, should I look at switching to the I series of props?

For comparison, my 2002 Four Winns 268 with that engine/drive uses an F4 duoprop. The previous owner said he had a D7 prop set on it for a while which gave him more speed at lower rpm, but I believe it was working (lugging) the engine harder that the F4 Prop set. The "D" props are aluminum, and I believe they are slightly smaller diameter. The "F" series (original on my boat) are stainless steel.

 

[Scott Danforth]

D7 props are going to be for a very light boat. Way too much pitch for your boat

I woul be looking for D3 or F3