# Re-proping a Yamaha 70 2 Stroke on 18 Waterman



## Smackdaddy53 (Dec 31, 2012)

Probably a 13 3/4 diameter 15 pitch 3 blade will get you close but there are so many blade shapes, rake, cup etc.
Yamaha 70 2 stroke on an HPX Tunnel here running a 13 3/4” 14 pitch triple cup 3 blade hitting 34mph but it’s a holeshot prop. Remove the triple cup and add one pitch to make up for it and you’ll get more top end but lose holeshot. A custom prop guy can get you EXACTLY what you need without guessing and messing with shelf props.


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## chrisbalgero (Dec 25, 2013)

Smackdaddy53 said:


> Probably a 13 3/4 diameter 15 pitch 3 blade will get you close but there are so many blade shapes, rake, cup etc.


Easy enough, thanks man.


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## Austin Bustamante (May 11, 2015)

Scd 3-16p


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## reallyshallow (May 19, 2010)

Austin Bustamante said:


> Scd 3-16p


^^^There’s your answer. If you have a jackplate you can go up to a 17p SCD3


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## No Bait / Lures Only (Apr 10, 2011)

U got a jack plate?


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## chrisbalgero (Dec 25, 2013)

ya I do have a jackplate, what speeds can I expect do you think with the SCD 3 16p or 17p? 
@Austin Bustamante @reallyshallow @No Bait / Lures Only


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## No Bait / Lures Only (Apr 10, 2011)

My f70la on 18x60 plate flat with scd3 x 15 36/38 mph gps @ 6100 rpm. My boat weight is 1200# rigged. Your boat probably 300# less so u should be able to touch 40 with ur 2 stroke. My gear ratio is 2:33, i think urs is 2:33 as well. Ur motor is 30 # less weight...


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## reallyshallow (May 19, 2010)

If you have a jackplate you will have better grip with the SCD 4 blade. I also had a jackplate on my Gordon and I was spinning a SCD 17 pitch 4 blade. You’ll have good grip jacked up all to the top, but don’t run it all the way up to long, you’ll overhead. I was seeing 37-39 depending on load, with my rpms at 5300-5500 depending on jackplate level. Hope this helps.


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## chrisbalgero (Dec 25, 2013)

Not against another 4 blade, but what it came with, I top out at 32. just looking for more top end, would love to touch 40 mph. I'm in LA so I take some long runs. Looks like I have the wrong prop. Its a Powertech SWW4R13. Also will I gain any MPG's with three blade vs. four blade?


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## chrisbalgero (Dec 25, 2013)

@reallyshallow what's your hole shot like?


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## Austin Bustamante (May 11, 2015)

chrisbalgero said:


> Not against another 4 blade, but what it came with, I top out at 32. just looking for more top end, would love to touch 40 mph. I'm in LA so I take some long runs. Looks like I have the wrong prop. Its a Powertech SWW4R13. Also will I gain any MPG's with three blade vs. four blade?


where you at in La? I have a scd 3-16p. I’m thinking about jumping up to a 17p. I have a caimen with a 70hp and a jackplate. Solo can hit 6k pretty easily and hit 37-38mph.


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## Poonphish (Feb 23, 2015)

chrisbalgero said:


> Anybody got suggestions on size and pitch? running a four blade now and looking for more top end. Apologies in advance if this has already been discussed, I couldn't find it though.





chrisbalgero said:


> Not against another 4 blade, but what it came with, I top out at 32. just looking for more top end, would love to touch 40 mph. I'm in LA so I take some long runs. Looks like I have the wrong prop. Its a Powertech SWW4R13. Also will I gain any MPG's with three blade vs. four blade?


I have a 70 2 stroke Yamaha on a HPXT. I HAD A Powertech PFS 4R 14pitch 13 1/4 diameter and really didn’t like the performance. Just went to a Powertech SWW 3R 13.5 diameter 3 blade. 14pitch.....runs so much better. I do not have a Jackplate , which everyone in Texas seems to have and I have been told by Jack Foreman that it’s pretty much useless without one. I know that Jack Foreman has probably forgotten more than I will ever know regarding props........Seems funny to me that it is SO HARD to get these boats dialed in as far as the propping goes. Very few HPXT owners seem to agree on a go to prop for a 2 stroke Yamaha. Love to hear more input on this and if anyone is looking for a Powertech PFS 4R 14pitch. 13 1/4” dia. I will make you a great deal or if you have a 3 blade you want to trade , let me know. If texting is easier my number is 239-980-4336. Thanks


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## No Bait / Lures Only (Apr 10, 2011)

Poonphish said:


> I have a 70 2 stroke Yamaha on a HPXT. I HAD A Powertech PFS 4R 14pitch 13 1/4 diameter and really didn’t like the performance. Just went to a Powertech SWW 3R 13.5 diameter 3 blade. 14pitch.....runs so much better. I do not have a Jackplate , which everyone in Texas seems to have and I have been told by Jack Foreman that it’s pretty much useless without one. I know that Jack Foreman has probably forgotten more than I will ever know regarding props........Seems funny to me that it is SO HARD to get these boats dialed in as far as the propping goes. Very few HPXT owners seem to agree on a go to prop for a 2 stroke Yamaha. Love to hear more input on this and if anyone is looking for a Powertech PFS 4R 14pitch. 13 1/4” dia. I will make you a great deal or if you have a 3 blade you want to trade , let me know. If texting is easier my number is 239-980-4336. Thanks


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## No Bait / Lures Only (Apr 10, 2011)

I have a pt red 3-17" to trade


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## chrisbalgero (Dec 25, 2013)

@Austin Bustamante I'm in Metairie. Id be interested to see how it preforms. What you asking?


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## reallyshallow (May 19, 2010)

chrisbalgero said:


> @reallyshallow what's your hole shot like?


Hole shot was good. Especially in shallow water, tabs down-jacked all the way up, smooth acceleration jumped right up.


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## Austin Bustamante (May 11, 2015)

chrisbalgero said:


> @Austin Bustamante I'm in Metairie. Id be interested to see how it preforms. What you asking?


Not sure I want to sell it yet, still trying to find someone who has a 17p for sale


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## Poonphish (Feb 23, 2015)

No Bait / Lures Only said:


> I have a pt red 3-17" to trade


Don’t know what you mean. Is it a red prop. What is pitch and diameter and what are you currently running it on. Thanks....John


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## No Bait / Lures Only (Apr 10, 2011)

Power tech RED series 3 blade -17" pitch x 13 1/4" diameter.


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## Smackdaddy53 (Dec 31, 2012)

Poonphish said:


> I have a 70 2 stroke Yamaha on a HPXT. I HAD A Powertech PFS 4R 14pitch 13 1/4 diameter and really didn’t like the performance. Just went to a Powertech SWW 3R 13.5 diameter 3 blade. 14pitch.....runs so much better. I do not have a Jackplate , which everyone in Texas seems to have and I have been told by Jack Foreman that it’s pretty much useless without one. I know that Jack Foreman has probably forgotten more than I will ever know regarding props........Seems funny to me that it is SO HARD to get these boats dialed in as far as the propping goes. Very few HPXT owners seem to agree on a go to prop for a 2 stroke Yamaha. Love to hear more input on this and if anyone is looking for a Powertech PFS 4R 14pitch. 13 1/4” dia. I will make you a great deal or if you have a 3 blade you want to trade , let me know. If texting is easier my number is 239-980-4336. Thanks


More input- 
On that hull and motor combination (same as mine) a Foreman 3 blade 13 3/4” diameter 14 pitch XXX cup is the prop.


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## Austin Bustamante (May 11, 2015)

Smackdaddy53 said:


> More input-
> On that hull and motor combination (same as mine) a Foreman 3 blade 13 3/4” diameter 14 pitch XXX cup is the prop.


What kind of speed do you get? I know holeshot is probably killer!


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## Smackdaddy53 (Dec 31, 2012)

Austin Bustamante said:


> What kind of speed do you get? I know holeshot is probably killer!


These are average load-
Cruises 28 @ 4500
34 @ 5500
36 @ 5800 but I don’t like running the true WOT, usually 30 @ 5200

I fished the only tournament I ever fish each year and won heavy trout and heavy red, missed the spot pot by 2 spots out of 41 teams this month and there were 4 SCBs/Simmons boats in the mix. Those are 75-80mph boats with 4 guys on a team. Three of us in a “weenie boat” chunking plastic almost swept it. It’s not the arrow, it’s the indian! 

Hole shot is half a boat length or less, it’s silly


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## chrisbalgero (Dec 25, 2013)

@Austin Bustamante let me know i am be interested in it, cause i have a buddy in mobile wanting the prop i currently have and it sounds like your a good midpoint.


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## Poonphish (Feb 23, 2015)

No Bait / Lures Only said:


> Power tech RED series 3 blade -17" pitch x 13 1/4" diameter.


What do you think that would run like on the boat I described


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## Austin Bustamante (May 11, 2015)

Hey I had that RED prop on mine. It ran good like mid 5k rpms, just had a hard time getting it to run in the jackplate.


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## Smackdaddy53 (Dec 31, 2012)

Austin Bustamante said:


> Hey I had that RED prop on mine. It ran good like mid 5k rpms, just had a hard time getting it to run in the jackplate.


Probably not enough cup


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## No Bait / Lures Only (Apr 10, 2011)

Poonphish said:


> What do you think that would run like on the boat I described


I ran it on mine un loaded n ran 40 mph gps @6300...running loaded 38..


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## Settin_hooks (Oct 24, 2019)

I just picked up a 08 Gordon waterman 18 with the F70 2 stroke and no jack plate. It has an SCD 3-14. Seems like I was seeing around 34-35 mph @6k rpms but I will have to double check that. 

Most of you seem like your running jack plates, I was told by the previous owner that it would lose a little draft if I installed one and he wouldn’t recommend it. What are your guys thoughts on this? From what I’ve read most seem to prefer them which makes sense to me on this boat..

And then of course the prop, is it worth me jumping up to the 16 or 17 if I decide to get a jack plate? will I lose a lot of hole shot? Should I go 3 blade or 4 blade still a bit confused on this.


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## State fish rob (Jan 25, 2017)

You’ll lose some draft every time you add weight to your skiff. Hopefully , the JP will add versatility.shouldnt hurt holeshot. I like more offset than not, if given the choice. 4 blade will help w hole shot & stern squat somewhat. Adding some cup to your existing prop will probably help too. Worth a try , before replacing, good luck


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## Smackdaddy53 (Dec 31, 2012)

State fish rob said:


> You’ll lose some draft every time you add weight to your skiff. Hopefully , the JP will add versatility.shouldnt hurt holeshot. I like more offset than not, if given the choice. 4 blade will help w hole shot & stern squat somewhat. Adding some cup to your existing prop will probably help too. Worth a try , before replacing, good luck


4 blades don’t always mean better hole shot just like 3 blades aren’t always better for top end. It’s actually just the opposite on some setups. Just clearing that up because I read and hear that common misconception quite often and it is misleading. I’d put my skiff with a 3 blade XXXcup against the exact same boat with any 4 blade as far as hole shot and also as an all around prop that gives great hole shot and top end.


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## michael.h (Sep 29, 2019)

I just picked up an 08 18' Waterman w/ F70 4 stroke and jack plate spinning a SCD4 15P. Trimmed out in calm conditions I'm hitting 37 @6.2k RPMs and I can get the engine up to 4.5-5 on the jack plate if I back off the throttle a bit. Hole shot is decent, I'm coming from a 2 stroke so it's hard for me to say.

The jack plate doesn't seem to have a huge effect on my speed though (1-2 mph if that). It is a huge plus for shallow water versatility but if you don't need it for your style of fishing then I'd save the $$$ and draft.

SCD3 16P might be in my near future, just wondering how far I could get it up on the jack plate


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## State fish rob (Jan 25, 2017)

Supposedly, if you get your Jack plate up & out ,motor trimmed etc....you’ll save fuel also. I adjust until spray around motor lays down. You’ll need a water pressure gauge to be on the safe side


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## No Bait / Lures Only (Apr 10, 2011)

State fish rob said:


> Supposedly, if you get your Jack plate up & out ,motor trimmed etc....you’ll save fuel also. I adjust until spray around motor lays down. You’ll need a water pressure gauge to be on the safe side


I have f70la on plate flat 18x60 scd3 15 36/38 gps @6100


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## Settin_hooks (Oct 24, 2019)

I’m mostly fishing in the mosquito lagoon area, seems like a jack plate is preferred by most on this hull. Going from the 14 3 blade to the 16 3 blade will give me a little more up top but I may lose a little hole shot right? I’m leaning towards installing a jack plate and trying the scd 3 blade 16 like others have recommend.


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## Smackdaddy53 (Dec 31, 2012)

Settin_hooks said:


> I’m mostly fishing in the mosquito lagoon area, seems like a jack plate is preferred by most on this hull. Going from the 14 3 blade to the 16 3 blade will give me a little more up top but I may lose a little hole shot right? I’m leaning towards installing a jack plate and trying the scd 3 blade 16 like others have recommend.


First thing you need to make notes of when propping a boat is wide open throttle RPM. If you are already hitting your maximum recommended RPM for your motor you don’t want to dog the motor by adding pitch. I think a good rule of thumb is each pitch changes your WOT RPM by 200-300rpm. There are other factors like rake, cup, diameter and blade shape that make a prop do a lot of different things.


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## Settin_hooks (Oct 24, 2019)

That being said I will add the plate and see what numbers I’m getting with the current prop. Thanks for the advice


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## Smackdaddy53 (Dec 31, 2012)

Settin_hooks said:


> That being said I will add the plate and see what numbers I’m getting with the current prop. Thanks for the advice


A compression or cavitation plate should drop RPM some due to getting more clean water to the prop so there’s less slippage.


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## No Bait / Lures Only (Apr 10, 2011)

reallyshallow said:


> If you have a jackplate you will have better grip with the SCD 4 blade. I also had a jackplate on my Gordon and I was spinning a SCD 17 pitch 4 blade. You’ll have good grip jacked up all to the top, but don’t run it all the way up to long, you’ll overhead. I was seeing 37-39 depending on load, with my rpms at 5300-5500 depending on jackplate level. Hope this helps.


3 blade will give better top end speed.


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## No Bait / Lures Only (Apr 10, 2011)

chrisbalgero said:


> Not against another 4 blade, but what it came with, I top out at 32. just looking for more top end, would love to touch 40 mph. I'm in LA so I take some long runs. Looks like I have the wrong prop. Its a Powertech SWW4R13. Also will I gain any MPG's with three blade vs. four blade?


Scd 3 blade will do d job top end pitch?


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## michael.h (Sep 29, 2019)

I ended up getting the SCD3 16P and can touch 40 with 1/2 tank and 2 guys @6200 rpm. Perfect prop for the F70-Waterman combo

Can also jack it up to 4 before it starts to blow out a bit.


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## not2shabby (Sep 14, 2016)

I'll add more noise to the conversation only because this prop has not been mentioned yet. PowerTech's Shallow Water Wheel (SWW) line is really solid for the 70 TLR. I have run two props on my 70 TLR and HB 17.8. The first was a PowerTech SWW3R16PYM90. I really liked the prop. Good hole shot and would top out at 36mph, or a little more running light. 

I had the opportunity to pick up a prop from Jack Foreman a couple months ago. The hole shot is excellent and I top out at about 34mph. I run around at 30 or 32 regardless of prop, so I like the benefit of the hole shot on the Foreman. I can jump up and run all the way up on the jack plate with the Foreman. I could not get on plane at 6 on the JP with the PowerTech.


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## Smackdaddy53 (Dec 31, 2012)

not2shabby said:


> I'll add more noise to the conversation only because this prop has not been mentioned yet. PowerTech's Shallow Water Wheel (SWW) line is really solid for the 70 TLR. I have run two props on my 70 TLR and HB 17.8. The first was a PowerTech SWW3R16PYM90. I really liked the prop. Good hole shot and would top out at 36mph, or a little more running light.
> 
> I had the opportunity to pick up a prop from Jack Foreman a couple months ago. The hole shot is excellent and I top out at about 34mph. I run around at 30 or 32 regardless of prop, so I like the benefit of the hole shot on the Foreman. I can jump up and run all the way up on the jack plate with the Foreman. I could not get on plane at 6 on the JP with the PowerTech.


Yep, I’ll take great holeshot and lose 2-3mph for sure.


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