prop advice

[othelloears]

I have a 1984 welcraft elite 200 that I repowered with a mercuiser 260 I am struggling to get some prop efficiency. I had a 19p solas 4 blade and was doing 42 mph at 4100 wot. I could cruise at 3000 rpm at 30mph. I went to a 4 blade hustler 17p and wot is 40 @ 4500 with 22. @ 3000. Really disappointed. Can anyone recommend a more efficient prop for this boat

 

[steelespike]

I'm surprised the Hustler didn't do better. I do wonder if perhaps the tach or speedo may not be reliable.Speed by gps is more reliable.
When reducing pitch you might lose some speed.
Your 19" had reasonable slip a little high 16% at 4100 and 42 mph.
And a respectable 18% slip at 3000 and 30. The Hustler had 18% at 4500 and 40.too high. and a rediculess 33% at 3000 and 22 mph.
These numbers are only as accurate as the info.GPS speed would help.
I don't know if a Spitfire 4 blade is available for your 260 but they have a good reputation for maintaining rpm and improving performance.
It would also appear that the same model as your 19 in a 17 or 18 would support your 19 numbers with the addition of the 17s rpm range.
If your 20 is a big heavy boat it may account for slightly elevated slip of the 19.

 

[othelloears]

Its a full resto (deck and stringers) .w epoxy which I think added a lot of weight. It is gps speed. I am going to double check tach . Would u stay 4 blade?

 

[steelespike]

A 4 blade should have better hole shot,stay on plane better at reduced throttle,grip better ,seem smoother and respond better around the dock.
A 3 blade may be faster.
Does the boat get up on the water well when you trim up?
Did the resto maintain uniform hull shape?

 

[othelloears]

This is what really doesnt make any sense. Even with the 19p 4blade the boat jumps out of the water even with 7 people gas and equip. It doesnt struggle at all. The only issue is the wont rpms. I have always believed there is something else going on keeping the wot rpms down

 

[Starcraft5834]

Your engine might be a little tired an 84.. id keep the 4 blade 17...stay at rec 4500 your engine will thank you

 

[Maclin]

You say you just repowered, what was in there before? Just wondering if the drive ratio is off, but does sound more like the engine is not tuned well yet.

 

[othelloears]

Repowered from a 228 to 260 (supposed to be 275). I also put on a remain carb and am not convinced that I am getting everything out of it I should. I just did more tests and biggest problem is struggling to stay on plane. With 4 blade 19 I was solid at 2900. W this 17p hustler I dont have solid plane until @3300.