I tested my new prop. where should I go now?

[rcl700]

I took my pontoon out for a test run yesterday. I had issues.

I had a new prop (Turning point Hustler 15p 13-3/4'') on the motor after rebuilding the lower unit. I think I picked the wrong prop . My max RPM was 4500 and I need 5500. I did get 26.6 MPH from my gps unit think I need togo from a 15p to a 13p to get in the torque band .


I have a 20ft pontoon with a 2004 tohatsu 90hp motor (the boat was unloaded - one flip flop seat, console, and two people.Im replacing the seating.

Turning point has a 13p 14'' prop do you think this would be a good replacement?

Thoughts please on what prop to put on. ( I still have a new turning point hub
that I would like to use)

 

[Texasmark]

Re: I tested my new prop. where should I go now?

Well the rule of thumb is 200 per inch so it looks like you only missed by 5 inches....too much pitch. Nice thing about Hustler is you can buy the prop only and use your existing hub.....if you pay attention to the new prop and the hub it requires. Will save you some bucks.

Mark

 

[rcl700]

Re: I tested my new prop. where should I go now?

So your saying you think it may need a 10p prop?

 

[trendsetter240]

Re: I tested my new prop. where should I go now?

Hey rcl, the thing about the turning point hustler prop is that it has a very aggressive rake and blade design. Not exactly suited for a pontoon boat at all in my opinion. Personally I found them to have poor low speed handling.

I have the hustler in 17p and my motor would turn it at 5100RPM. I also have a OMC 17p prop that will turn at 5500RPM under exactly the same conditions.

A more accurate estimate on the RPM difference you will see is Old RPM X (old Pitch / new pitch). So for you a 13p TP Hustler would turn about 5200RPMs. This rule only applies if you stay with the exact same model, nuber of blades and material prop.

If I were to make a educated guess based upon your info you should look at a 4-blade in a 13 pitch. Something like the Solas Amita Alum. is an inexpensive option. Or a 3-blade will give you some more RPM but less grip in the lower RPM ranges.

 

[rcl700]

Re: I tested my new prop. where should I go now?

So using old rpm x old p \ new p

A 12p turning point would put me at (5600rpm)
perfect but

They don't make a 12p.

13p or 11p

I feel like if I go to 4 blade I have to start the guess work all over to get a baseline. I don't have the time or money to keep ordering props and fighting to take them back.

I'm stuck on where togo with this.

 

[trendsetter240]

Re: I tested my new prop. where should I go now?

So using old rpm x old p \ new p

A 12p turning point would put me at (5600rpm)
perfect but

They don't make a 12p.

13p or 11p

I feel like if I go to 4 blade I have to start the guess work all over to get a baseline. I don't have the time or money to keep ordering props and fighting to take them back.

I'm stuck on where togo with this.

You know what you're right. And anyone that says they know exactly what prop you need is full of it. It truly is a trial and error game.

FWIW I think you'd be happy with the 13p 4-blade Slolas Amita as an all around prop. But if you are really concerned with RPM then go with the 3-blade Solas 13p. The Solas will give you more RPM than the TP hustler.

 

[rcl700]

Re: I tested my new prop. where should I go now?

You know what you're right. And anyone that says they know exactly what prop you need is full of it. It truly is a trial and error game.

FWIW I think you'd be happy with the 13p 4-blade Slolas Amita as an all around prop. But if you are really concerned with RPM then go with the 3-blade Solas 13p. The Solas will give you more RPM than the TP hustler.

What kind of rpm do you think I can get out of the four blade sloas 13p?
Will the four blade pull the RPMs down more then the 3 blade?(the four blade does have a smaller diameter 13-1/4" vs. 14")

I read everywhere including the manual that the motor should be running in the range of 5200 - 5800 rpm that's why I seem concerned with the RPMs ( maybee overly)

Thanks for the info this realy helps:redface:

 

[Texasmark]

Re: I tested my new prop. where should I go now?

What kind of rpm do you think I can get out of the four blade sloas 13p?
Will the four blade pull the RPMs down more then the 3 blade?(the four blade does have a smaller diameter 13-1/4" vs. 14")

I read everywhere including the manual that the motor should be running in the range of 5200 - 5800 rpm that's why I seem concerned with the RPMs ( maybee overly)

Thanks for the info this realy helps:redface:

I wouldn't say that you may be "overly" concerned. I think there is enough data out there, including personal experiences, that testify to the fact that top of the range is where you NEED to be.

Mark

 

[rcl700]

Re: I tested my new prop. where should I go now?

Well I just got the solas 4 blade prop 13p . I will try it out on the lake on Monday to see if it brings my rpm range up where it needs to be. I also raised my motor up on the transom from the top hole to the bottom one. I was told it was too low. The may help also.

I'll post an update.

 

[Silvertip]

Re: I tested my new prop. where should I go now?

A 90 should have no trouble twisting a 13P.

 

[rcl700]

Re: I tested my new prop. where should I go now?

well the 13p four blade put my rpms where they needed to be.
5400RPM. I did not gain much speed though. 2 or 3 mph
max speed was 29 mph.

Thanks to everyone for your input.

 

[trendsetter240]

Re: I tested my new prop. where should I go now?

well the 13p four blade put my rpms where they needed to be.
5400RPM. I did not gain much speed though. 2 or 3 mph
max speed was 29 mph.

Thanks to everyone for your input.

Hey rcl, that's good to hear. Nothing wrong with 5400RPM. Plus that leaves you room for improvement in other areas like motor height, weight distribution etc on your boat.

Happy boating!

 

[rcl700]

Re: I tested my new prop. where should I go now?

Hey rcl, that's good to hear. Nothing wrong with 5400RPM. Plus that leaves you room for improvement in other areas like motor height, weight distribution etc on your boat.

Happy boating!

I will need a taller transom if I'm going to get anymore hight. I'm using the bottom bolt hole. Thanks agin.

 

[trendsetter240]

Re: I tested my new prop. where should I go now?

Hey rcl, what is the model number for your motor? Models 90A EPTO and 90A EFO have a range of 5000RPM to 5500RPM. If this is correct then your new prop is perfect for your setup.

I got this information from the Tohatsu website.

Here is the link: http://www.tohatsu.com/tech_info/own_man_pdfs/Toh60C_70C_90A_120A2_140A2.pdf

Also in another section of their site the following quote (in big, bold, capital red letters):

"UNDER NO CIRCUMSTANCES SHOULD YOU EVER USE A PROP WHICH WILL ALLOW YOUR OUTBOARD TO OPERATE ABOVE THE OUTBOARD'S RECOMMENDED MAXIMUM RPM's!"

Link : http://www.tohatsu.com/accessories/prop.html

 

[rcl700]

Re: I tested my new prop. where should I go now?

90B TLDI.
I think I'm in a good spot as far as rpms go. now I need to get the motor to stop fouling plugs I'll be good.

 

[Texasmark]

Re: I tested my new prop. where should I go now?

90B TLDI.
I think I'm in a good spot as far as rpms go. now I need to get the motor to stop fouling plugs I'll be good.

Maybe you want to start a new thread on this subject. There are numerous solutions to that problem. Oh and congrats on getting your prop problem solved.

Mark

 

[Abraham]

Re: I tested my new prop. where should I go now?

not sure on that question.

 

[Bob_VT]

Re: I tested my new prop. where should I go now?

not sure on that question.

Here is a good piece of iboats advice..... If you are not sure of an answer or have no viable input ....... just do not answer. Obtaining the last word by telling someone "good luck with that" or "not sure on that question" could do more harm then good.