I don't have a 4 stroke - I prefer 2 strokes but the Suzukis are good engines - I know several people with them.
To be honest I would normally go for the biggest engines - say 2x 250hp as you will often save fuel as they don't have to work too hard as you use much smaller throttle openings.
Having said that the 175s are quite a bit lighter than the 200hp and above so a good choice.
The 28 cabin is pretty heavy boat, the twin 175 setup is great and we have done several installations but to be honest i think you have to go for V6 (for example Suz DF200) instead of 4, the torque and cylinder volume will probably take down the consumption on that heavy boat, the 175 have to work much harder to get boat up in plane and you will have higher revs in cruisning speed etc etc.
Go for the V6, dont think you will regret it, and a plus is that boat will be more quiet.
I have to agree, the 175s will probably use more fuel than the 200s on a heavy boat like a Protector 28 Cabin. Maybe even quite a lot more.
Unless of course you drive it wide open all the time
The engines will also be less stressed and the boat will hold its value better in my opinion.
By the way, if I had the cash the Protector would be what I'd go for.
Put 250's on it, you'll have a better boat with a stronger resale value which would offset the additional purchase cost. I bet there are some very good deals out there at the moment.
