2007 Hewes Redfisher 16 Yamaha C90 (2 stroke)

[Capt Obvious]

Good Morning

First post here, I looked for an introduction thread but didn’t see one so here I am. I appreciate all of the information shared so far. 
I am in Central Fl and use my new to me little Hewes in northern Brevard and Volusia waters and plan some freshwater fishing also now that I have a smaller boat. The engine is mounted one hole up or on the second hole from the top. From the information that I have found that seems to be the preferred location, I do not have a Jack Plate. 
The boat came with two props, the one that was on it was a Power Tech RXB 15p 4 blade. I called PT and they just said that it was an interesting choice by the previous owner but nit one they would recommend for the boats intended use. The engine would only get about 4700 rpm without trimming it to the point of sucking air. 
the second prop is a Yamaha K 16, 13-1/4 3 blade. With that prop I am able to reach 5000-5100 rpm trimmed up about half way, much further I will be sucking air. 37-38 mph. It does 30 at 4000 rpm. 
Power Tech recommends an SCD 16 P in 4 blade, that is a 13” prop. They think that will  allow me to more comfortably reach the 5300 to 5500 rpm range at about the same 37-38 mph speed. I’m not sure that I have a question outside of if I intend to run the boat at more of a cruise speed like 30 would the new recommended PT prop be better for the engine even not running WOT? 
also just looking for a similar setup. I see similar on here but not with a lot of details about rpm and speed and such with specific prop sizes. Anybody have the same rig? 

[HoneyB]

I would spend a little more time with the props you have before spending money for new. It really doesn’t seem like either of them are preforming terribly.
 

If the three blade gets you on plane quickly and has good rpm it may be the better of the two props you have now. 

[Capt Obvious]

Thanks for your reply HoneyB. 
Yeah the three blade gets on plane pretty good. I fished yesterday in Mosquito Lagoon, it was the first ti

e that I used the boat with a moderate load. I lowered the tabs before hitting the gas and it does jump right up. Without dropping the tabs it’s not miserable. I spoke to a seasoned Hewes dealer and Yamaha Mechanic on Friday and he MDI acted that for that particular Hewes Hull I shouldn’t need to be trimming it up much or any to hit full RPMs. 

[linesider 159]

Personally I think you will want a 15 pitch not a 16. That boat needs help getting on plane and propping it closer towards 6k rpm will help. 
 

The best prop I ever ran was a solas 15 pitch. Unfortunately I can't remember the model

[Capt Obvious]

22 hours ago, linesider 159 said:

Personally I think you will want a 15 pitch not a 16. That boat needs help getting on plane and propping it closer towards 6k rpm will help. 
 

The best prop I ever ran was a solas 15 pitch. Unfortunately I can't remember the model

Thanks, sans the rpm’s I was thinking the same thing. The C90 is 5500 max but my thought process was that both props that I have are both 16p 13-1/4”, what PT is recommending is a 4 blade 16p but at 13”. I don’t know all of the prop witchcraft but 1/4” is pretty small split across four blades. I do have a local guy with the props in stock, I didn’t know at the time that he would let me try them until we got it right but have learned that since asking the question. I’m chomping at the but to get a day to run those tests. 

[croakersmoker]

@Capt Obvious I saw 41 MPH at 5400 RPM with a 13.25" 17p 3 blade. This prop was really beat up and out of shape too. I never had trouble getting on plane either. Seemed like the dream prop for my 1997 Bayfisher 16. Your hull shape is a little different, but weight and load should be the same. 

I just repowered with a new VF90LA and started with a new 13" 17p prop that wasn't enough pitch. Still playing with it.

[Capt Obvious]

On 8/15/2022 at 3:13 PM, croakersmoker said:

@Capt Obvious I saw 41 MPH at 5400 RPM with a 13.25" 17p 3 blade. This prop was really beat up and out of shape too. I never had trouble getting on plane either. Seemed like the dream prop for my 1997 Bayfisher 16. Your hull shape is a little different, but weight and load should be the same. 

I just repowered with a new VF90LA and started with a new 13" 17p prop that wasn't enough pitch. Still playing with it.

Thanks, from what I can find my model year hull is about 400# heavier than yours. I dropped the boat off yesterday for a carb job. I’ve put more hours on the boat in two months than the previous owner did in seven years. I just want to make sure that at WOT I’m not lean and getting fuel fuel. Once that is done I will dive more into the prop testing next week. The boat did come with a PT RXB prop as well and I ran that Sunday. PT says it’s the wrong prop but it sure does grip better when zig zagging through the islands. The three blade blows out easily. The guy doing the carbs was a Hewes dealer for several years and he told me that for my model what PT is suggesting (SCD4 16P) is the deal for that hill and engine. He said it would get about 52-5300 Rs and that was where they could get that boat working the best. In my mind I feel like the 15p would be the ticket but he will let me try them both. 
I’ll follow up here next week with some data. 

[Capt Obvious]

Thanks for all of the direction so far. Well I got the carbs done. They really needed some love. The engine is an 07, it had 205 hours on it when I got it. It was only run for 30 hours in seven years prior to me owning it. It started fine and ran pretty good. A little rough at idle and rough in the lower ranges. She smooth and quieter now though. The 4 blade PT RBX (RXB?) that came on it still wouldn’t spool up good. I think I said 15 P earlier but it’s 16. The 16 P ported Yamaha 3 blade I had worked better especially after the carb job but it blows out pretty easy turning. It doesn’t plane as good as the RBX but not too bad with a little tab. I could still only get to 5k ish without trimming and what seems like a lot to get it higher. I ran a 16P PT SCD 4 blade and it wouldn’t get to those RPMs, still 4700 or so WO. I ran the same SCD prop in a 15 today. By myself, full fuel, no trolling motor but two batteries up front. I was super happy, it would plane in about three Mississippi with about three seconds of tabs down. It would run up to 5100 with no trim at 35 mph. It would hit 39 at 5400 with the trim at 3 and still grip in turns. It cruised well at 4400 at 30 mph and the steering was light and the engine quiet. I was ready to put it on the trailer and head home.  I was fortunate enough to also get to try the same SCD prop in a 14p. Wow, planes in two Mississippi with no tabs.  It would run up to about 5300 with no trim at 35 mph. The catch is when I trimmed up I didn’t gain anything, probably just slipping. The cruise was at about 4700 at 30 but the steering was heavy, so likely it would have been happier at lower Rs and speed. It was windy and choppy in freshwater (it’s my understanding planning is salt is easier).  I’m afraid if it was flat and glassy with no wind the 14 wouldn’t be enough.
My questions. Would you rather be a little fat on the prop?  What are some thoughts about when I add a passenger or two? Would the 14 just slip with the extra weight and the numbers would go backwards ie RPMs up and speed down? 
I almost want to try an SCD 3 in a 15 P. It’s still semi cleaver and stern lifting but less mass to spin, may be the sweetest spot. 
I realize that I probably won’t be running WOT but I’m understanding this correctly part of proper prop selection is that it would hit top RPMs. 
Hope I’m not wearing you guys out because it’s wearing me out. 
 

[Moderator]

Dialing in props for some boats is a journey.. We get it !

Stick with it and hopefully the right owner will chime in and save you some time and $..

MM