jcolew Posted March 22, 2017 Report Share Posted March 22, 2017 Hi, New to forum and have a 2001 16 RF which I re-powered with a Suzuki DF90A four cycle. Just finishing engine break in period and need to pick a proper prop. Previously I used my Yam 2 cycle 90 four blade SS 12/15 and it had great hole shot but rev'd too high. Looking at the weight of the boat from the old brochures I estimate the weight w/o motor at 1310 and with this motor 1643. Has anyone re-powered a 16 with a DF90 or am I a pioneer? If there is some guidance out there I'm all ears ... hate spend forever and a dollar figuring this out. Link to comment Share on other sites More sharing options...
MPFit Posted March 22, 2017 Report Share Posted March 22, 2017 Well run what you have on it now; see where it puts you in the rpm range. Too high revs- go up in pitch. Too low drop some pitch. Find a prop that offers the benefits you'd like (top end, holeshot, bow or stern lift etc.) if going from a 3 to four blade general consensus is to drop pitch also. There needs to be a starting point to help you in a direction unless (as you have asked) someone has already done this. Either way good luck and keep us posted! Link to comment Share on other sites More sharing options...
geeviam Posted March 22, 2017 Report Share Posted March 22, 2017 Welcome! There's a Boat Test section on the Suzuki Outboard web page at the following link: http://www.suzukimarine.com/Product Lines/Outboard Motors/Products/DF90/2012/DF90A.aspx Looks like a 14 x 19P 3-blade was being tested on skiffs of similar weight. That seems a bit tall for a 90 HP to me, but I don't have experience with the high-thrust gear case (lower gearing) that the Suzukis are known for. Like MPFit said, less pitch would be needed in a 4-blade of course. Good luck! There are a few members here who will be anxiously awaiting your results. Link to comment Share on other sites More sharing options...
jcolew Posted March 23, 2017 Author Report Share Posted March 23, 2017 Thanks geeviam ... Suzuki only makes and suggest three blades ... Correct me if I'm wrong but I've always thought a four blade was best for hole shot and turn cavitation with a bit of sacrifice in top end. Since I mainly scramble thru skinny water fishing for reds staying on plane at mid speed, I'm not so concerned about top end performance. I had been all over that boat list and tried to find the closest hull shape and weight that compared to the RF16 but I didn't find anything close of the ones I knew about and I don't know enough about the others. The mechanic who installed my motor suggested Powertech in Louisanna so I'm gonna give them a call today. So far the motor is extremely quiet, incredibly smooth, and wonderfully responsive. Just rev's too high 6800+ ... gotta get it down to 6000-6200. Link to comment Share on other sites More sharing options...
lurem Posted March 23, 2017 Report Share Posted March 23, 2017 Which prop came with the motor? If you purchased new can you do an prop exchange of any type with the dealer? Link to comment Share on other sites More sharing options...
jcolew Posted March 23, 2017 Author Report Share Posted March 23, 2017 Bought the motor w/o prop i've been using the prop from the Yammy 90 2 cycle which is a 13/15 four blade SS I talked to Powertech today and the first recommendation is their 4 blade SS PTR18 (13 1/2, 18) but they have a Hewes guru named Marcus who is going to review that and call me back ... and apparently he is a regular here going by Funky Monkey ... So Marcus if your reading this thanks in advance. Link to comment Share on other sites More sharing options...
geeviam Posted March 23, 2017 Report Share Posted March 23, 2017 37 minutes ago, jcolew said: Bought the motor w/o prop i've been using the prop from the Yammy 90 2 cycle which is a 13/15 four blade SS I talked to Powertech today and the first recommendation is their 4 blade SS PTR18 (13 1/2, 18) but they have a Hewes guru named Marcus who is going to review that and call me back ... and apparently he is a regular here going by Funky Monkey ... So Marcus if your reading this thanks in advance. Sounds like a good plan! Marcus (Funky Monkey) will get your boat running at peak performance, in short order. He has saved many of us from wasting valuable time on the water, testing the wrong props. Link to comment Share on other sites More sharing options...
jcolew Posted March 23, 2017 Author Report Share Posted March 23, 2017 15 minutes ago, geeviam said: Sounds like a good plan! Marcus (Funky Monkey) will get your boat running at peak performance, in short order. He has saved many of us from wasting valuable time on the water, testing the wrong props. Waiting with Gulp scented breath ... Link to comment Share on other sites More sharing options...
jcolew Posted March 23, 2017 Author Report Share Posted March 23, 2017 Talked to Marcus (nice guy) and it's clear as mud ... Apparently 2001 was the year that the RF16 went from a boat needing bow lift to stern lift (or the other way around) somewhere in production mid year ... So if It needs bow lift then the Powertech PTR 18 or 19 is the need But if it needs stern lift then Powertech LNR 18 or 19 possibly 20 is the need both 4 blade So I'm headed out this weekend armed with more internal questions to answer before I order one ... wish me luck, god speed or something. Link to comment Share on other sites More sharing options...
jcolew Posted March 28, 2017 Author Report Share Posted March 28, 2017 I imagine this was the model that needs more stern lift but I moved the 24 volt batteries to the forward hatch prior to testing ... Ran the boat out this weekend with a power tech 13.25"D 4 blade SS RKB 13P Great hole shot, Spot on lift, Great in tight turns with no cavitation, 20-22 MPH at 4000-4200 RPM/s ... Still rev'd very high 6800+ (hit limiter) Marcus is sending me same prop with 18 pitch Link to comment Share on other sites More sharing options...
MPFit Posted March 28, 2017 Report Share Posted March 28, 2017 Nice. Higher pitch will get those revs down- does yours have trim tabs? I think almost all RFs do. If so- getting on plane should be a breeze and the cruising speed with the 4 blade should be nice and maneuverable. Let us know how your test comes out with the 18p Link to comment Share on other sites More sharing options...
jcolew Posted March 28, 2017 Author Report Share Posted March 28, 2017 2 hours ago, MPFit said: Nice. Higher pitch will get those revs down- does yours have trim tabs? I think almost all RFs do. If so- getting on plane should be a breeze and the cruising speed with the 4 blade should be nice and maneuverable. Let us know how your test comes out with the 18p Yup got trim tabs ... but all my testing was done w/o using them ... I'm anxious ... weather has been great and spring run of Cobia is near ... Link to comment Share on other sites More sharing options...
MPFit Posted March 29, 2017 Report Share Posted March 29, 2017 I do my testing without the tabs also. When I went from a 17p 3 blade to my current 20p 4 blade my holeshot got much worse (I was able to spin that 17p VERY quickly). However; with trim tabs down, holeshot was exactly the same - and for efficiency and comfort I tab down every time I go to get on plane anyway. Once on plane I tab up, then trim up, and often wind up tabbing down just a hair for some porpoising control since trimming down doesn't always fix it and I lose rpms when I trim compared to tab. I feel I've got it dialed in now and it's a fun aspect of boating anyway Link to comment Share on other sites More sharing options...
jcolew Posted March 30, 2017 Author Report Share Posted March 30, 2017 On March 29, 2017 at 8:07 AM, MPFit said: I do my testing without the tabs also. When I went from a 17p 3 blade to my current 20p 4 blade my holeshot got much worse (I was able to spin that 17p VERY quickly). However; with trim tabs down, holeshot was exactly the same - and for efficiency and comfort I tab down every time I go to get on plane anyway. Once on plane I tab up, then trim up, and often wind up tabbing down just a hair for some porpoising control since trimming down doesn't always fix it and I lose rpms when I trim compared to tab. I feel I've got it dialed in now and it's a fun aspect of boating anyway What boat and motor are you running and what top end can you reach with that 20P? Link to comment Share on other sites More sharing options...
MPFit Posted March 30, 2017 Report Share Posted March 30, 2017 RF 18. Yamaha VMAX150 Carbed. 51mph at 5400 rpm with light load Link to comment Share on other sites More sharing options...
jcolew Posted March 31, 2017 Author Report Share Posted March 31, 2017 On 3/30/2017 at 0:10 PM, MPFit said: RF 18. Yamaha VMAX150 Carbed. 51mph at 5400 rpm with light load Love that boat ... had one sold it (mistake), bought a Hewes LT20 with 200Vmax (selling) love the boat goes 60+ but doesn't corner in the skinny water that's why when I came across this super clean RF16 I grabbed it ... it's working for me great just gotta get the right prop/boat/motor combination ... Link to comment Share on other sites More sharing options...
jcolew Posted April 6, 2017 Author Report Share Posted April 6, 2017 The drama continues ... ran the 4blade 13.25 18P yesterday hole shot 2 1/2 boat lengths (not so good) and top revs 5500 ... so given the need for higher revs and better hole shot Marcus is suggesting a 16P to gain 200-300 revs per 1" of pitch and get the revs into the 6000 range and improve hole shot ... now I'm waiting for that. His feelings on this boat is that hole shot should be around 1 to 1 1/2 boats lengths and top end around 36-38mph with a 90 horse. Link to comment Share on other sites More sharing options...
MPFit Posted April 6, 2017 Report Share Posted April 6, 2017 I'd agree with him; and with those results from the 18p- I think you and Marcus are spot on with that 16p. Keep us posted! Link to comment Share on other sites More sharing options...
jcolew Posted April 13, 2017 Author Report Share Posted April 13, 2017 The drama continues ... ran the 4blade 13.25 18P yesterday hole shot 2 1/2 boat lengths (not so good) and top revs 5500 ... so given the need for higher revs and better hole shot Marcus is suggesting a 16P to gain 200-300 revs per 1" of pitch and get the revs into the 6000 range and improve hole shot ... now I'm waiting for that. Well the prop came and well it was the wrong prop in the wrong box ... a 15P was packed in a 16P box ... tried it any way but too low of a pitch maxed rev-limiter I'm gonna ask for a 17P (16 1/2 would be perfect) I'm getting a tad wary of this process but love where its headed Link to comment Share on other sites More sharing options...
geeviam Posted April 13, 2017 Report Share Posted April 13, 2017 If the PT 13.25 x 17P 4-blade ends up being very close, but still too large - try a Mercury SpitFire X7 13 x 17P 4-blade if you can get your hands on one. That's what I use. You will not be disappointed! Link to comment Share on other sites More sharing options...
geeviam Posted April 13, 2017 Report Share Posted April 13, 2017 34 minutes ago, geeviam said: If the PT 13.25 x 17P 4-blade ends up being very close, but still too large - try a Mercury SpitFire X7 13 x 17P 4-blade if you can get your hands on one. That's what I use. You will not be disappointed! Wow! Just checked and they raised the price of the Merc SpitFire X7 prop. MSRP is now $578.00! The cat's out of the bag now! Link to comment Share on other sites More sharing options...
lurem Posted April 13, 2017 Report Share Posted April 13, 2017 Jcolew, You started with a 12x15 and were hitting 6800, Then you went to a 13.25x18 and got 5500 (you went up in diameter so that is harder for you boat to push compared to the 12" diameter you started with) and only got 5500 rpm's. Now you are back down to a 16 pitch, which is only 1 inch larger than you started but the diameter has changed. Looking at the Suzuki tests that Geeviam posted I see boats in your weight class running 13.5 to 14" diameter and 19 pitch. I would have thought the 18 pitch Marcus sent would be dead on and give you a 38-40 mph top speed. You said in you first post that you put your Yamaha prop on the Suzuki. Is the hub hollow and you had to buy the correct sleeve to adapt it to your new outboard or the prop hub was pressed on permanently and it was a direct fit? You also mentioned that 2001 was the year for some boats porpoising and some liking to fly the bow. Which did you determine you have? Give me the model prop and I can tell, Did you get a PTR stamped prop? Link to comment Share on other sites More sharing options...
jcolew Posted April 20, 2017 Author Report Share Posted April 20, 2017 On April 13, 2017 at 1:47 PM, lurem said: Jcolew, You started with a 12x15 and were hitting 6800, Then you went to a 13.25x18 and got 5500 (you went up in diameter so that is harder for you boat to push compared to the 12" diameter you started with) and only got 5500 rpm's. Now you are back down to a 16 pitch, which is only 1 inch larger than you started but the diameter has changed. Looking at the Suzuki tests that Geeviam posted I see boats in your weight class running 13.5 to 14" diameter and 19 pitch. I would have thought the 18 pitch Marcus sent would be dead on and give you a 38-40 mph top speed. You said in you first post that you put your Yamaha prop on the Suzuki. Is the hub hollow and you had to buy the correct sleeve to adapt it to your new outboard or the prop hub was pressed on permanently and it was a direct fit? You also mentioned that 2001 was the year for some boats porpoising and some liking to fly the bow. Which did you determine you have? Give me the model prop and I can tell, Did you get a PTR stamped prop? Good catch, thanks for commenting and I should have corrected that post ... Ill try and answer all your points. I never looked at the original prop and took the word of the mech assistant but the original was a 13.25/13p 4blade ss In the mean time Marcus and my mechanic played telephone tag and Marcus re-sent a 13.25 16p that was supposed to be in the last box ... I'll try that tomorrow The props in all the Suzuki tests are 3blade so I'm told they will run faster (I'm more about hole shot and handeling so I'm hoping to use a 4blade) ... if this prop works I'll be a happy camper but I may need to go up to a 17p ... hell I may end up with a 3blade suzuki and all this was for nothing. Hole shot and running with the neutral prop and batteries forward has been level. So I'm assuming this model was one that needed stern lift and moving the batteries corrected that. I know this post is all over the place but so are all the opinions ... I'm ready to focus on fishing and be done with this ... Link to comment Share on other sites More sharing options...
Moderator Posted April 21, 2017 Report Share Posted April 21, 2017 Great plan.. Dial in the prop and fish that boat all over the place ! Looking forward to the photos. Mod-1 Link to comment Share on other sites More sharing options...
jcolew Posted April 24, 2017 Author Report Share Posted April 24, 2017 Guys thanks for all the moral support but I think I'm done here ... Marcus sent the 4blade SS Neutral lift 16p before we could discuss sending the 17p Here is the 16p up shot ... No trimming Max RPM 6200 35MPH Running RPM 5000 28-30 MPH Skinny water RPM 4000 20 MPH No cavitation except at full speed on initial tight turn (minimal) Hole shot 1-1 1/2 boat lengths, no tabs, full bait well, 3/4 fuel tank one passenger 170lbs Full turn hole shot effortless again 1-1 1/2 boat lengths I'm sure I can get it more speed out of this Suzuki 90 but I'm not sure it will perform any better ... Gonna try it again with two people and if it underperforms I may drop the 4blade and go to the Suzuki 3blade. If it performs as well as with one person then I'm done. Link to comment Share on other sites More sharing options...
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