# HP Upgrade



## out-cast (Jan 27, 2009)

Congrats Jerry. Make sure to post your results!!


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## riptide (Dec 31, 2009)

What year model 2strokes can you do this to , and how much does a new reed assembly cost. Ive been looking for a 15 but there is a 9.9 yami for sale localy. this might be an option does ,the 15 have any thing diffrent besides the reed assembly. Very interested i this btw


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## TomFL (Oct 2, 2007)

If it flows more air, then it's gotta have more fuel otherwise things get fuzzy and white inside....

Did you up the jetting/go to a larger carb???


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## saltflyer (Jul 22, 2008)

> What year model 2strokes can you do this to , and how much does a new reed assembly cost. Ive been looking for a 15 but there is a 9.9 yami for sale localy. this might be an option does ,the 15 have any thing diffrent besides the reed assembly. Very interested i this btw


Mine is a 2006, which is the same as later models. I have compared the 9.9 to the 15 and all parts (except the reed valve assembly) are identical, even the carb and jets. The carb may need to be tuned - I will find out when I run it this weekend.

I ordered the reed valve assembly from boats.net for $48.65 +shipping.


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## riptide (Dec 31, 2009)

Thats sweet , hope you will report back how it runs when you test it out . i might be doing a 9.9/15 conversion 2


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## Yoreese (Oct 15, 2009)

Port and polish that cylinder and get a few more HP!


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## saltflyer (Jul 22, 2008)

I have been trying to get out and test the HP upgrade - it's either been raining, really cold or I have been busy.  Well today I finally got out.

With the stock prop (9.25" x 9p) she ran like a champ....at 5600 rpm (100 above max recommended operating range) I got 21 out of her.  That was also with a good load...I wanted to get it optimum with a standard days fishing load.  That's not bad considering (before the upgrade) I was get a top speed of 13.5 mph and only 4800 rpm with the same load as today.

She was sucking a bit of air every now and again...so I think the final prop is going to be a PowerTech stainless steel 9.25" x 8p with cupping - I am going down 1" to accommodate for the cupping.  The cupping should also help get a mile or two more per hour out of her.

Ordering the prop tomorrow!


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## rkmurphy (Nov 2, 2008)

> I have been trying to get out and test the HP upgrade - it's either been raining, really cold or I have been busy.  Well today I finally got out.
> 
> With the stock prop (9.25" x 9p) she ran like a champ....at 5600 rpm (100 above max recommended operating range) I got 21 out of her.  That was also with a good load...I wanted to get it optimum with a standard days fishing load.  That's not bad considering (before the upgrade) I was get a top speed of 13.5 mph and only 4800 rpm with the same load as today.
> 
> ...


If she's already above the max RPM, stick with the 9P and add cupping to it. Should put you right where you want it!


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## TomFL (Oct 2, 2007)

Not only that but you might pick up RPM's/speed going to stainless as well. 

-T


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## saltflyer (Jul 22, 2008)

I agree and after sleeping on it, I have decided to stick with the 9p cupped. I'll post the final results.


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## TomFL (Oct 2, 2007)

In my mind I just can't figure out how this is working with the stock 9.9 carb and jets, but it seems as if it is. 

You've piqued my interest on doing this and I looked up my little nissan 9.9 and it's the same motor as the 15.......Hmmm....

I'll let you be the guinea pig for a few more weeks before I do anything though... 

-T


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## saltflyer (Jul 22, 2008)

Actually, Whitesnook was the guinea pig. He upgraded his 9.9 to a 15 quite a while ago. I know that Mercs are more difficult to upgrade...not sure about Nissan or other makes??


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## saltflyer (Jul 22, 2008)

Ok...the prop is installed! Going to run it this weekend. I'll let everyone know the results.


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## natez (Dec 26, 2009)

That is f~ing awsome. ;D


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## saltflyer (Jul 22, 2008)

Ok...here are the final results with the PT SRT 9p loaded for a day of fishing - 5540 rpm at WOT - 22.8 mph. Jumps up quick and absolutely no ventalation or cavitating.


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## pescador72 (Aug 6, 2008)

Wow! Awesome prop, and motor. I want one of those props so bad.


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