# Guesstimating pitch on a 30hp Yammi



## SWFL_Gheenoe (Aug 24, 2017)

Hey guys, I bought a old 30 horse yammi a few weeks back, ran nicely for my first trip on my Classic Gheenoe, but now its starting to show symptoms of a cylinder not firing. Bringing it to my local shop next week, but in the mean time - I have absolutely no idea what size prop is on this thing. Its a nice 3 blade stainless, but havent been able to find any size specs on it. 
Id like to get a spare prop for it, but also wouldnt mind making that "spare" a potential performance improvement. 
I got a tiny tach that ill install as well, but even at that, how do I decide what pitch to go with for the spare? I feel like I see the 13p talked about most often with these engines, but that could also mean next to nothing.


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## Smackdaddy53 (Dec 31, 2012)

Take it to a prop shop and they can put it on a pitch jig and tell you.


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## SWFL_Gheenoe (Aug 24, 2017)

Didnt even know that was a thing! Will do, thanks


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

SWFL_Gheenoe said:


> Hey guys, I bought a old 30 horse yammi a few weeks back, ran nicely for my first trip on my Classic Gheenoe, but now its starting to show symptoms of a cylinder not firing. Bringing it to my local shop next week, but in the mean time - I have absolutely no idea what size prop is on this thing. Its a nice 3 blade stainless, but havent been able to find any size specs on it.
> Id like to get a spare prop for it, but also wouldnt mind making that "spare" a potential performance improvement.
> I got a tiny tach that ill install as well, but even at that, how do I decide what pitch to go with for the spare? I feel like I see the 13p talked about most often with these engines, but that could also mean next to nothing.


I have a similar motor, 2 stroke 25 2 cylinder Modified Yamaha on a Spear Glade x. Tried 3 props on it with a tiny tac for engine speed, the perfect prop for me was the Power Tec SRA 3 x 12" pitch 5850 rpm. Tried a Solas 13" and it was tooooo much pitch and cup as it had been modified 5100 rpm. Also tried the Turbo Hot Shot 12" 6800 rpm+ too much rpm as it hit the rev limiter. Try to get a prop to keep your rpm higher in the range so when it is loaded it will be spot on. The Solas is for sale if you need a spare. Been using the Power Tec fo 4 years now with no issues....


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## SWFL_Gheenoe (Aug 24, 2017)

No Bait / Lures Only said:


> I have a similar motor, 2 stroke 25 2 cylinder Modified Yamaha on a Spear Glade x. Tried 3 props on it with a tiny tac for engine speed, the perfect prop for me was the Power Tec SRA 3 x 12" pitch 5850 rpm. Tried a Solas 13" and it was tooooo much pitch and cup as it had been modified 5100 rpm. Also tried the Turbo Hot Shot 12" 6800 rpm+ too much rpm as it hit the rev limiter. Try to get a prop to keep your rpm higher in the range so when it is loaded it will be spot on. The Solas is for sale if you need a spare. Been using the Power Tec fo 4 years now with no issues....


Just need to convince myself to bite the bullet on a powertec... Ive heard very good things about the SRA3's, in both 12" and 13"


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

Power Tec SRA3 is the prop of choice for little light skiffs or flat boats, very happy with mine. You might be able to buy a used s/s prop on this site....list what you need, you never know until you ask.....


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

SWFL_Gheenoe said:


> Hey guys, I bought a old 30 horse yammi a few weeks back, ran nicely for my first trip on my Classic Gheenoe, but now its starting to show symptoms of a cylinder not firing. Bringing it to my local shop next week, but in the mean time - I have absolutely no idea what size prop is on this thing. Its a nice 3 blade stainless, but havent been able to find any size specs on it.
> Id like to get a spare prop for it, but also wouldnt mind making that "spare" a potential performance improvement.
> I got a tiny tach that ill install as well, but even at that, how do I decide what pitch to go with for the spare? I feel like I see the 13p talked about most often with these engines, but that could also mean next to nothing.


Try changing the plugs as that worked with my motor was showing the same symptoms...Also try borrowing a prop as buying new is expensive just to test...


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

SWFL_Gheenoe said:


> Hey guys, I bought a old 30 horse yammi a few weeks back, ran nicely for my first trip on my Classic Gheenoe, but now its starting to show symptoms of a cylinder not firing. Bringing it to my local shop next week, but in the mean time - I have absolutely no idea what size prop is on this thing. Its a nice 3 blade stainless, but havent been able to find any size specs on it.
> Id like to get a spare prop for it, but also wouldnt mind making that "spare" a potential performance improvement.
> I got a tiny tach that ill install as well, but even at that, how do I decide what pitch to go with for the spare? I feel like I see the 13p talked about most often with these engines, but that could also mean next to nothing.


6000 rpm is a good start for the motor..


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## SWFL_Gheenoe (Aug 24, 2017)

Little further update - 
Messed around with trim/jp height on the 30 today. Had a bit of trouble getting the prop to bite right as the boat hops on plane. It will blow out and slowly accelerate till it bites again and then maxes out at 5200-5400 depending on jp height. 
I tried gradual throttle, flooring it, and everything in between, but the motor still didnt want to hook up until the jp was almost all the way down (cav plate 2" above the bottom of the hull, at 14" behind the transom)

Would this be a lack of cup problem?

I picked up a sra4 11p, just waiting for the right thrust washer to get here so I can try it out too.


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

SWFL_Gheenoe said:


> Little further update -
> Messed around with trim/jp height on the 30 today. Had a bit of trouble getting the prop to bite right as the boat hops on plane. It will blow out and slowly accelerate till it bites again and then maxes out at 5200-5400 depending on jp height.
> I tried gradual throttle, flooring it, and everything in between, but the motor still didnt want to hook up until the jp was almost all the way down (cav plate 2" above the bottom of the hull, at 14" behind the transom)
> 
> ...


Waiting for the new performance numbers....


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## RunningOnEmpty (Jun 20, 2015)

I ran a 3 cylinder yamaha 30hp on a lt25 with a power tech SRA3 13P that ran great. I'm 250 lbs and with another big guy the boat ran just fine. If you are on the skinny side and fly fish with minimal gear the 13p might not be enough? The classic is a faster boat so that's another reason a 14p might work? A 4 blade should lower the rpm's around 200 rpm give or take. My sra prop did slip a little while getting up but it grabs hard at high speeds. A standard prop will just continue slipping.


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## SWFL_Gheenoe (Aug 24, 2017)

RunningOnEmpty said:


> I ran a 3 cylinder yamaha 30hp on a lt25 with a power tech SRA3 13P that ran great. I'm 250 lbs and with another big guy the boat ran just fine. If you are on the skinny side and fly fish with minimal gear the 13p might not be enough? The classic is a faster boat so that's another reason a 14p might work? A 4 blade should lower the rpm's around 200 rpm give or take. My sra prop did slip a little while getting up but it grabs hard at high speeds. A standard prop will just continue slipping.



Im almost positive my current prop is a 13p, but ill take a better look at it! 
Ive run into some technical difficulties since I was last out... Trying to do some preventative maintenance and clean the water jackets and I ended up breaking a head bolt in the block... 
Waiting for parts to come in till I can bolt it all back up and then try the SRA4

Keep the tips and suggestions coming - I appreciate them all!


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## SWFL_Gheenoe (Aug 24, 2017)

Well... Spent a while fiddling with the thrust washer and came to the conclusion that it just plain wont work on my motor. I guess thats why they make different props for different motors  
Sidenote - anyone want to buy a new PowerTech SRA4 11p for a Tohatsu/Nissan?
Sidenote #2 - anyone have a SRA3 or SRA4 in the SWFL area for a Yamaha? Id love to try it out.


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## RunningOnEmpty (Jun 20, 2015)

Try selling it on the gheenoe forums. That's a good pitch for the 4 strokes. Do you have the 3 cylinder yamaha?


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## SWFL_Gheenoe (Aug 24, 2017)

RunningOnEmpty said:


> Try selling it on the gheenoe forums. That's a good pitch for the 4 strokes. Do you have the 3 cylinder yamaha?


Might actually try and get it rehubbed for a Yamaha. Wish I wouldve thought of that in the first place ._. 
And yeah, '95 3 cylinder 2 stroke 30


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## RunningOnEmpty (Jun 20, 2015)

Same year I had. Mine had a cooling issue as well when I first got it. I removed the thermostat and it was full of debris. Stay away from the scream and fly or boat racing facts forum or you will be learning about all the cool mods for your motor. I ran 40hp carbs on mine along with a bunch of other mods. 39 mph was my best run before I hit a rock


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## SWFL_Gheenoe (Aug 24, 2017)

RunningOnEmpty said:


> Same year I had. Mine had a cooling issue as well when I first got it. I removed the thermostat and it was full of debris. Stay away from the scream and fly or boat racing facts forum or you will be learning about all the cool mods for your motor. I ran 40hp carbs on mine along with a bunch of other mods. 39 mph was my best run before I hit a rock


Those dang rocks pop up out of nowhere! Bummer man. Have any parts you wanna sell?!


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## SWFL_Gheenoe (Aug 24, 2017)

Update on the rehubbage - turns out the SRA4/hatsu/nissan just flat out wont work on my Yamaha. Oh well! 
My local prop shop is going to put some more cup into my Stiletto and keep the pitch, in hopes of being able to elevate/trim the motor to achieve higher RPM, while the cup knocks the RPM down and maintains bite. 

At the moment this is the cheapest option, and in my twisted brain it kinda sounds like it should work!


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## RunningOnEmpty (Jun 20, 2015)

SWFL_Gheenoe said:


> Those dang rocks pop up out of nowhere! Bummer man. Have any parts you wanna sell?!


I sold it to someone that wanted all the custom modified parts. I had too many problems with the prop shaft after souping it up. It was probably making 40hp and the little prop shaft wasn't happy about it while running super skinny.


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## SWFL_Gheenoe (Aug 24, 2017)

Bit of an update for those that were curious - 
Had the Stiletto cupped a bit by my local shop, in hopes of being able to get enough bite so I could raise the engine enough to get the lost RPM's back. 
Lots of hope, but not enough  
Turned 5100 RPM's today WOT with the cupped prop (was able to get another inch or so out of the JP) 

I havent ruled out the possibility of a mechanical problem, but im leaning more towards the current prop I have being heavily pitched, more like a true 14p. 

Anyone disagree with buying a SRA3 13p and going from there?


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## RunningOnEmpty (Jun 20, 2015)

Show me a picture of the spark plugs before wasting money on a prop.


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## SWFL_Gheenoe (Aug 24, 2017)

Top is top cylinder, middle is middle cylinder and bottom is... you guessed it 

Im not a plug genius, so please tell me that this is my problem!


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## RunningOnEmpty (Jun 20, 2015)

My old 30hp plugs always had a light brown color like your bottom plug. All 3 always looked the same unless I had a dirty carb. Are those plugs fairly new?


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## SWFL_Gheenoe (Aug 24, 2017)

RunningOnEmpty said:


> My old 30hp plugs always had a light brown color like your bottom plug. All 3 always looked the same unless I had a dirty carb. Are those plugs fairly new?


Yep. about 10 hours on them.
Im thinking of asking my local shop about the possibility of tuning the carbs. Could that be the difference?


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## RunningOnEmpty (Jun 20, 2015)

The low speed mix screws could be out? Did you check the fuel pump and clean the carbs properly?


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## SWFL_Gheenoe (Aug 24, 2017)

No clue where the low speed mix screws would be - but I’ll ask. And yes, cleaned the pump w/new gaskets and carbs cleaned


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## RunningOnEmpty (Jun 20, 2015)

Did you remove the high and low speed jets along with the orifice tubes? Sometimes everything needs a soaking in carb cleaner to get them clean or a ultra sonic cleaner. The adjustment screws are on the top left side of each carb. It's a small flat head screw with a spring behind it. I would mark them and then gently run them in until they stop. Do not force them in! Count the turns as you go. I think a good starting point is 1 1/2 to 1 3/4 turns out from lightly seated. Those screws should've been removed during the cleaning process.


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## RunningOnEmpty (Jun 20, 2015)

This isn't a good example because it's a different motor, but it's helpful.


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## Smackdaddy53 (Dec 31, 2012)

I would have gone to a prop guy by now. I have no patience for things limiting my fishing time.


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## SWFL_Gheenoe (Aug 24, 2017)

Smackdaddy53 said:


> I would have gone to a prop guy by now. I have no patience for things limiting my fishing time.


Ahaha this was by no means limiting my fishing time - the boat scoots along just fine with the current prop, I was just trying to figure out where the other RPMs went.

Im currently limited right now by my truck anyways... Broke down yesterday, with symptoms of either a bad crank position sensor or a clogged IPR screen.... yay ._.


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## Smackdaddy53 (Dec 31, 2012)

SWFL_Gheenoe said:


> Ahaha this was by no means limiting my fishing time - the boat scoots along just fine with the current prop, I was just trying to figure out where the other RPMs went.
> 
> Im currently limited right now by my truck anyways... Broke down yesterday, with symptoms of either a bad crank position sensor or a clogged IPR screen.... yay ._.


Good luck getting that CKP sensor out. I’m about to replace mine too. Guessing you have a 6.0...


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## SWFL_Gheenoe (Aug 24, 2017)

Smackdaddy53 said:


> Good luck getting that CKP sensor out. I’m about to replace mine too. Guessing you have a 6.0...


Got a call from the shop today... Leaky STC fitting ._. 
I Love love LOVE my truck, but it left me stranded for the first time yesterday, so were gonna have a talk when it gets back from getting fixed


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

If you still have prop troubles with the 30, I have a Solas 3 blade s/s 13" n extra cup for sale, $100.00 plus the ride.


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