Repower power

[Sangster21]

Planning on re powering a 20 Sangster that currently has an inline 6 Mercruiser MC165. Am I correct in my understanding that inboards were hp rated at the crank and new outboards are rated at the prop? Planning on sourcing a newer used outboard and wonder if a 150hp modern outboard would at least be equivalent to the old power? Don't see the need to go 40knots, but don't want to be under powered either. Thoughts?

 

[sly_karma]

150 hp is a good match for 20 ft planing hull.

 

[scott craven]

I would suggest a 200 HP might be a better match.
Once you load up with fuel, gear and bodies the 150 HP may not be enough.

 

[kaelc]

Do your research on the displacement of the different 150-200hp engines, I feel like there is a big difference between them. You can compare. https://ww2.arb.ca.gov/new-vehicle-...ve-orders-my2023-spark-ignited-marine-engines

 

[Coyote Spooner]

I used to have a 18’ Sangster, with a MC165. I bought it with freeze cracked engine. I sourced out an old truck block and rebuilt it. I added a Shadbolt cam, which was supposed to up the power to 185hp. That boat flew!!! It did over 50mph. The big benefit of the inline 6, was the torque. It would pull a wakeboarder or skier out of the hole like nothing. After that boat I had a 21’ Trophy, with a 175hp V-6 MC. That boat was underpowered!! When I replaced that engine, I went with a 220hp MC MPI. Much better match. Sangsters are a heavier boat than a Trophy. So I’d be inclined to put a 225 or 250 hp. I’ve learned it’s better to have more power! Motor won’t work as hard and fuel economy will probably be the same, due to lower rpm at cruise speed.

 

[Rayvon]

I owned a Sangster with the same motor (165) GM,and I think a150 would be borderline enough power,as Scott says a 200 would work and agree w/Kaelc there is a lot of difference in the 200 motors,4 or 6 cylinders.

 

[SpringVelocity]

200hp minimum. 150hp is really borderline on that size boat.

 

[seachicken]

I'm not familiar with Sangsters weight or hull design but our podded 20' hull DE has a 225 Yamaha and I really wouldn't go any less on it but wouldn't say no to 250. I can go almost 40 knots WOT but cruise about 28 knots at about 4000 RPM. You won't regret extra power but you definitely will if you come up short. As @Coyote Spooner said easier on the motor and fuel economy at lower cruise throttle.

 

[pescador]

200 or go home. No man ever complained about too much HP.