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2013 18' HPX-V, F115 Prop - Spitfire 19P or 21P

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Happy new year guys!  New member here and have learned a lot from you reading the forum here.  Just purchased a 2013 HPX-18 with standard F115 and it is an awesome performing boat.  Currently running the stock yamaha K-21 prop and getting speeds of 46-48mph with motor mounted in lowest position.  I am looking for a prop with better holeshot as the K-21 has alot of bow rise trying to plane and slow planing characteristics.

I have seen very good feedback in the past on this forum regarding performance of the Merc Spitfire X7 prop on this HPX18 but it appears there are some that got the 21 pitch spitfire and needed to go back to the 19 pitch due to RPMs not maxing out.  I am loaded usually with two average size peeps, trolling motor and 3 batteries.  It feels like the 19pitch X7 may be the best choice but wanted your feedback before pulling the trigger.  Also, if I go with the spitfire, do you recommend I raise the motor a hole or two? I am not running a jackplate.

Many Thanks

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How many RPM are you turning the K 21 yamaha prop you have and is the yamaha pro series in good shape ?  I have a 21 pro series yamaha and a mercury spitefire X-7 that mercury racing has blueprinted. I can turn my yamaha 21 more RPM than I can turn my blueprinted Merc . No two boats or props are exactly alike so your numbers may not be the same as mine . On my set up I can turn my yamaha 21 300 more Rpm than I can turn my merc prop.  So if your bost and props perform close to mine if you can turn your yamaha 6300 RPM  you should be able to turn the merc only 6000 RPM .  If your boat performs like mine the Merc 19 will have a fantastic hole shot but may be a pitch to small . That would make the 21 a pitch to tall . Only way to know for sure would be to test one.  

 

 

 

 

 

 

 

 

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8 minutes ago, dabear said:

How many RPM are you turning the K 21 yamaha prop you have and is the yamaha pro series in good shape ?  I have a 21 pro series yamaha and a mercury spitefire X-7 that mercury racing has blueprinted. I can turn my yamaha 21 more RPM than I can turn my blueprinted Merc . No two boats or props are exactly alike so your numbers may not be the same as mine . On my set up I can turn my yamaha 21 300 more Rpm than I can turn my merc prop.  So if your bost and props perform close to mine if you can turn your yamaha 6300 RPM  you should be able to turn the merc only 6000 RPM .  If your boat performs like mine the Merc 19 will have a fantastic hole shot but may be a pitch to small . That would make the 21 a pitch to tall . Only way to know for sure would be to test one.  

 

DaBear - Thx for the input.  I can only turn the K21 to about 5900 and that is trimmed high.  I have the standard F115 so I think it's max rpm is 6000rpm.  My prop is in good shape.  If I remember reading your posts, you are running the SHO 115 which may be why you can spin those props more RPM than my motor.  How much load are you running with those #'s you quoted and what position is your motor mounted?  Jackplate? 

 

 

 

 

 

 

 

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It's no secret around here that I love the Merc SpitFire X7.  The problem is that Mercury does not make it in a 18 pitch or 20 pitch.  An 18 pitch would be perfect for my Redfisher 16, and a 20 pitch would probably be perfect for your HPXV 18 (based on Dabear's numbers).  There is a big gap in top-end RPMs between the different pitch sizes on a SpitFire X7.

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I think you are correct GEEVIAM with the RPM gap.  I had a smaller flats skiff that I ran an X7 spitfire on and went from a 15pitch to a 13pitch and the diameter of the 13pitch was larger than the 15pitch so I think the Merc props change a lot among the various pitches.  That spitfire I ran on the smaller skiff was the best prop ever(and I tried a bunch) so I agree that these props are the end all be all.

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If your turning a pro series 21 5900 trimmed out to the max than I would steer you towards the 19 spitefire X-7 . ( spitefire is harder to turn RPM than that yamaha K-21) . They have a good hole shot but the way merc did the progressive pitch design top end RPM doesnt come easy .  Hope you can find one to test  before you buy . As geeviam said " there is a big gap in top-end RPMs between the different pitch sizes on a SpiteFire X-7 ". Joe R

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Many Thanks.  It is too bad Merc doesn't offer exchanges similar to Powertech.  Do you think a prop guy could adjust the pitch on an X7 just like any other prop or not?  Can you recommend a good prop guy  - maybe the guy you mentioned that labbed your prop?

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16 hours ago, HPX FAN said:

Many Thanks.  It is too bad Merc doesn't offer exchanges similar to Powertech.  Do you think a prop guy could adjust the pitch on an X7 just like any other prop or not?  Can you recommend a good prop guy  - maybe the guy you mentioned that labbed your prop?

HPX FAN , who ever you send your new spitefire X-7 prop to make sure that the prop shop knows exactly what changes you want and need to have done, example I am not in the RPM range that I want to be at W.O.T. I need to be able to turn 200 more RPM. Tell them what performance gains you want to get and ask if they can rework your prop to get the gains you want. If you are looking for a 2 mph increase in speed and 200 more RPM make sure you both know that is what you need . Ask if they can rework the prop to get what you need . Its easy for a shop to get you more RPM but not as easy to get the RPM increase and speed . If they say they can try but may not be able to get you what you ask for than save your money and dont send it. Good luck 

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Bear  - Thanks for the additional input.  Will be sure to have the conversation you mentioned with the prop shop before committing.

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I have an 2011 18 HPX with the yami 115 with 415hours.  Same battery, trolling motor setup as the original poster normally fishing two.  I bought the skiff used and I am not sure what prop is on it, but its a 3 blade.  My motor is mounted in the lowest spot. Prop in in good shape no major dings or anything I can tell.

Topped out I am only spinning 5400 rpms on the tack.  I do not have a maxed out gps speed but I believe it is mid 40's as my previous boat was near the same speed.

Any ideas on whats going on with the low RPM's? or what props I should be looking at for overall top end?  I make a lot of longer runs and having the extra speed would be optimal.

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I would suspect you have a 21 pitch Yamaha pro series prop.  You should try trimming up more to get to 6000rpm and closer to 50mph.  That boat likes to be trimmed high to where you are throwing rooster tail and riding on the pad.  Tabs must be all way up.

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20 hours ago, Stx4wheeler said:

I have an 2011 18 HPX with the yami 115 with 415hours.  Same battery, trolling motor setup as the original poster normally fishing two.  I bought the skiff used and I am not sure what prop is on it, but its a 3 blade.  My motor is mounted in the lowest spot. Prop in in good shape no major dings or anything I can tell.

Topped out I am only spinning 5400 rpms on the tack.  I do not have a maxed out gps speed but I believe it is mid 40's as my previous boat was near the same speed.

Any ideas on whats going on with the low RPM's? or what props I should be looking at for overall top end?  I make a lot of longer runs and having the extra speed would be optimal.

Being you like how the Pro Series Yamaha rides but just need less pitch You should try the new series PRD-3 PowerTech prop that is just hitting the market I would think a PRD-3 in a 19 or 20 pitch may be what you need  E mail marcus@ptptop.com . He has all the inside information about the new prop ,plus is very familar with the HPX . Joe R

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1 hour ago, conocean said:

Man.....I always learn so much for dabear. Thanks Joe! 

Conocean, I just wanted to let anyone that has been looking for a hard to find K series Yamaha Pro Series prop that Yamaha stopped making . Power Tech has a new series prop that should be a great replacement prop for the pro series.So if you like the yamaha pro series than check out this new series by power tech called PRD-3 (PR for Pro and D for The size in PT line up D is the mid HP ) . For more info contact Marcus @ power tech he is the go to guy for info about this new model prop.  Joe R 

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17 hours ago, conocean said:

Man.....I always learn so much for dabear. Thanks Joe! 

x2.  Dabear is Da Man!  When he shares some knowledge, I pay close attention too.

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2 hours ago, geeviam said:

x2.  Dabear is Da Man!  When he shares some knowledge, I pay close attention too.

X3

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Thanks so much I appreciate and am flattered by the compliments but you all need to know that I enjoy sharing things that  I have tried that worked out for me. (Easier to make them go slower than faster)We all have spent lots of time and money with research and testing props that did not do what we thought they should of. Its kind of cool when we run a few that worked well and made a difference. I have picked up a bunch of information on the forum from members that have shared information about fishing lines, poles,.have had members tell me about fishing spots, had members let me follow them in areas that I have never fished. Over the years I have got way more from this forum than I give . Thanks again Joe R

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After discussions on the spitfire, I purchased an Evinrude Rogue 4 blade prop used prop from another forum group member.  This is a 13" diameter, 19pitch prop very similar to the spitfire.  Tested this morning on freshwater lake and it ran overall much better than the 3 blade 21Pitch pro series yamaha prop.  It ran top speed of 48mph at 6000rpm.  The boat planed flatter and overall the boat seemed to handle much better in turns and didn't lose grip even with motor trimmed to max rpm.  Could stay on plane with trim tabs all the way down at 12mph as well.  Much better midrange acceleration. Did not jack rabbit start due to hub needing breaking-in but I am assuming it will have much better holeshot as well.

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