OK... looking for your thoughts

[Buckman]

We have a 2013 24SLX with express tube and a Yamaha 150. I am new to this, but something does not seem right about the performance. Even with a light load (2 adults) the best speed (GPS) we have obtained is 28.9 MPH with a 1/2 tank of fuel. When we are tubing and taking corners, the speed drops from 18 MPH to 10 MPH BOOM! There is tons of cavitation. Have verified with the dealer that it is the 'right prop' for the motor and the pontoon (Yamaha Reliance Series 15-M 14 1/2) But with my level of experience they could tell me that the fastest speed should be 22 MPH and that I am getting amazing performance out of it and I wouldn't have the experience to know I was being steered wrong. :huh: Which is why I am asking for thoughts and ideas from those with much more experience! Oh forgot to add that it seems the boat sits quite low in the water on the backside like the darn thing is 'Butt Heavy'. There are lots of other pontoons at our dock that do not sit in the water like ours... they are all pretty level but they are regular pontoons... ours is the only triple (with the express tube that is)

 

[cwag911]

My thoughts: The express tube from whar I understand is shorter than the outer tubes which brings the bow up. Do you have strakes? While running, do you trim up the motor or is it all the way down? While taking turns the motor, if trimmed up has to be lowered. With that, I think your boat is too slow. What is your WOT?

 

[Buckman]

My thoughts: The express tube from whar I understand is shorter than the outer tubes which brings the bow up. Do you have strakes? While running, do you trim up the motor or is it all the way down? While taking turns the motor, if trimmed up has to be lowered. With that, I think your boat is too slow. What is your WOT?

WOT is 28.9 MPH with just two adults onboard. Last weekend had 4 adults and 3 kids on and was pulling my husband water skiing, it was a fight to get 23 MPH WOT to keep him on top of the water! I do have it trimmed down on the turns. I am at a loss. Becoming quite unhappy with our purchase now.

 

[cwag911]

WOT meaning rpm's with the hammer down when you're at top speed. We'll need both numbers. RPM and speed.

 

[Wild and Free]

20 or 25 inch engine shaft / transom? What hole is the engine mounted in and what rpms are you turning at wot straight line top speed? Not knowing if you have strakes, not having any strakes would be a killer for what you are asking the boat to do, when I had my sps and my esp I have to keep it trimmed down a lot further than normal driving with my 20 inch shaft to keep things hooking up and not cavitating while pulling tubers or skiers but even at that if i carve a hard enough corner applying a lot of throttle I will still blow out a bit.

I have the same prop and love it on my yammy 150 esp. I have 2 other props you could demo if you send me a PM to meet locally and try. I have 2 factory Yamaha 15 1/4 X 15 one in aluminum and one in Black stainless they both worked very well on my sps boat but the black stainless was a bit much for the esp, I gained about 150 rpms going to the 14 1/2 X 15 reliance prop and kept the same speed.

 

[Calamus]

Wow we have the spa with a 150 Yamaha 15 p prop hit 40 with 2 adults and 2 kids in the boat.

 

[Buckman]

WOT meaning rpm's with the hammer down when you're at top speed. We'll need both numbers. RPM and speed.

Sorry, wasn't thinking I guess.... the RPM top has been 5000 and the speed is 28.9 MPH

 

[Buckman]

20 or 25 inch engine shaft / transom? What hole is the engine mounted in and what rpms are you turning at wot straight line top speed? Not knowing if you have strakes, not having any strakes would be a killer for what you are asking the boat to do, when I had my sps and my esp I have to keep it trimmed down a lot further than normal driving with my 20 inch shaft to keep things hooking up and not cavitating while pulling tubers or skiers but even at that if i carve a hard enough corner applying a lot of throttle I will still blow out a bit.

I have the same prop and love it on my yammy 150 esp. I have 2 other props you could demo if you send me a PM to meet locally and try. I have 2 factory Yamaha 15 1/4 X 15 one in aluminum and one in Black stainless they both worked very well on my sps boat but the black stainless was a bit much for the esp, I gained about 150 rpms going to the 14 1/2 X 15 reliance prop and kept the same speed.

Let me try to answer your points!

1.) 20 Inch

2.) Mounted on the lowest position to put the prop lower into the water.

3.) RPM 5000 and MPH 28.9

4.) Yes we have lifting strakes.

 

[Wild and Free]

Strakes on the center tube only or on all 3 tubes?

All is correct except you are over propped if you are only getting 5K rpm you should be as close to 6k rpm as possible for best performance. I think my Black stainless would be too much prop for you as well but I would still let you try it just for trial purposes I think the aluminum would do better. If you want to try them shoot me a PM for contact info you are in my general area. I will be up at Sakakawea over the labor day weekend.

Bill

 

[Buckman]

Strakes on the center tube only or on all 3 tubes?

All is correct except you are over propped if you are only getting 5K rpm you should be as close to 6k rpm as possible for best performance. I think my Black stainless would be too much prop for you as well but I would still let you try it just for trial purposes I think the aluminum would do better. If you want to try them shoot me a PM for contact info you are in my general area. I will be up at Sakakawea over the labor day weekend.

Bill

Bill, the strakes are on all 3 tubes. We will be up at the lake both this weekend and over Labor Day. May have to PM you!

 

[Wild and Free]

OK so you have the SPS tube package, you have definate issues then, you should at least be in the low 30's for speed on a 24' boat with a 150 and your rpms are definately too low. I can tell you that the sps tube package doesn't turn well at all and takes a ton of power and they do blow out and cavitate as they are not meant for cornering, My 07 was a 22' sps package with the 150 and it did not like trying to corner at all, it did what you describe yours is doing but I didn't loose that kind of speed when cornering mine would run 41-42 light loaded perfect conditions with the black stainless 15 1/4 X 15 yamaha prop, I had to keep it trimmed almost all the way down to keep it from cavitating or blowing out real bad while cornering with tubers behind me.

Just for kicks If I were you I would crawl under the dash and look at the back of the tach and make sure the switch is in the correct position, the switch will be marked 4-6-8 for how many cylinders your engine is, yours should be set at 4, even my 07 was set wrong when i got it.

I have to work all this weekend so won't see the water until labor day weekend. Oh The joys of shift work at the coal mines, work one day have one day off then work 7 straight this coming week.

What area do you boat at on sakakawea?

Definately shoot me a message so we can meet up one day. We will most likely be at sakakawea state park in pick city.I will bring both props with me.

 

[Wild and Free]

Well now I am confused, I looked at the pics of your boat in your gallery and you do not have the sps tube package as you do not have strakes on the outside of the outer tubes, are you sure you don't have strakes on the center tube only and performance foils on the inside of the outer tubes if that is possible with the express tube package ? That would answer why it doesn't get any more speed other than what would be gained from getting the rpms up about 500-800 rpms.

Look at the link below to see what you have for tube setup.

http://www.benningto...ent=performance

 

[lakeliving]

He has the express tube but I don't see stakes on all the toons. Hard to tell what is on the side of the toons along with the express based on the photos in the gallery. I would guess mid 30s without strakes as kaydano's 24 sslx will do 42 with the express 6 strakes and a 150. Seems slow and rpm's are down as well.

 

[Buckman]

Well now I am confused, I looked at the pics of your boat in your gallery and you do not have the sps tube package as you do not have strakes on the outside of the outer tubes, are you sure you don't have strakes on the center tube only and performance foils on the inside of the outer tubes if that is possible with the express tube package ? That would answer why it doesn't get any more speed other than what would be gained from getting the rpms up about 500-800 rpms.

Look at the link below to see what you have for tube setup.

http://www.benningto...ent=performance

Ok, here is a close crop of the tubes, it does have the strakes on both sides of the center tube and the insides of the outside tubes.

 

[cwag911]

I vote on wrong prop. The rpm's are too low at WOT.

 

[lakeliving]

I agree with Carl, with those strakes the boat should be going faster and at a higher rpm for sure.

 

[Wild and Free]

Ok you have strakes on the middle tube and you have performance foils on the inside of the outer tubes like the esp boats have those are not strakes. It should corner better than an sps package.

 

[Ben & Suzy]

I'd be checking the throttle linkages to make sure that it's getting full travel to WOT. IMO, that seems more logical than too much prop pitch. A 15p should be just fine and push that boat into the mid to upper 30's........even with no strakes at all.

 

[Wild and Free]

I'd be checking the throttle linkages to make sure that it's getting full travel to WOT. IMO, that seems more logical than too much prop pitch. A 15p should be just fine and push that boat into the mid to upper 30's........even with no strakes at all.

This has crossed my mind as well.

 

[Buckman]

This has crossed my mind as well.

Alrighty then.... how does one go about throttle linkages? Myself I have no mechanical abilities... but Dave is pretty good at that kinda stuff!