Stainless Steel Prop for 1990 2Cyl 40hp Johnson

[rebel16fisherman]

Hey guys,

I am new to the forum as of today.

Last year I bought a 1991 Lund Rebel 16 SS with a 1990 40hp Johnson on it. I am currently running the factory original aluminum prop on it at 15" pitch. I can do about 27mph at 5500-6000rpms. Trimming up the motor seems to make no difference in speed. I have been contemplating going to a stainless steel propeller and have no idea which prop would be a good fit for this application. I have looked into Michigan Wheel Ballistic, Turbo Hot Shot, and Stiletto Triad props.

I am looking for any advice in this situation considering that I am just getting in to the stainless market. I would like a little more top end speed and would be willing to give up some hole shot to get it.

Thanks

 

[steelespike]

Re: Stainless Steel Prop for 1990 2Cyl 40hp Johnson

Welcome,
27 seems reasonable though slightly low.
I think we need to confirm if your setup is good.
is your speed by GPS? We need you to be more accurate with the rpm.
Accurate speed and rpm is critical. Is the prop in excellent condition?
Also the rpm and speed should be with a light load.
Is the antivent plate(just above the prop) about even with or slightly above the bottom?

You can use a straight edge to check.
At this point a ss prop could just be a bandage over a poor setup.

 

[rebel16fisherman]

Re: Stainless Steel Prop for 1990 2Cyl 40hp Johnson

To be more clear:

-I am running at 27.4 (GPS Speed) at 5900 rpms

-I am the only one in the boat with 2 marine batteries

-The antivent plate is 1/2 inch above the bottom of the boat

-The propeller is in decent shape, there is a tiny nic in one of the three blades. No paint is missing at all except that tiny nic.

 

[jestor68]

Re: Stainless Steel Prop for 1990 2Cyl 40hp Johnson

Since your WOT rpm range is 4500-5500 rpm, and you're turning 5900 rpm with a 15"; it would be appropriate to switch to a 17" to get your rpm down where it's supposed to be ( 5500 rpm ) and gain some speed.

A Solas or Turning point aluminum prop will give you stainless-like performance.

 

[rebel16fisherman]

Re: Stainless Steel Prop for 1990 2Cyl 40hp Johnson

Assuming that I go up to a 17" pitch, would I see any gains over alluminum by going to stainless steel?

 

[steelespike]

Re: Stainless Steel Prop for 1990 2Cyl 40hp Johnson

At 5900 the calculator indicates your near perfect prop has about 20% slip, really high.
A 15" prop is pretty typical for your application. I think before a prop change I would verify the tach.
Perhaps borrow a shop tach.

 

[rebel16fisherman]

Re: Stainless Steel Prop for 1990 2Cyl 40hp Johnson

I will mess around with the tach this weekend, I know a shop technician that lives nearby.

In general though just for my knowledge, if i purchased an stainless prop in the pitch that i decide on in the future, will i see any gains over an aluminum prop? There is a big price difference but i would be willing to pay more if it is worth it.

 

[steelespike]

Re: Stainless Steel Prop for 1990 2Cyl 40hp Johnson

Its really difficult to come up with exact numbers when going to a ss prop.
Improvement usually is across the board but could vary from a few tenths to a few mph.
When making changes it is usually suggested to make one change at a time.
If you don't have any venting(cavitation) issues you may be able to raise the motor some more.
Do you fine tune your trim?
Is there a hydrofoil or whale tail on the motor?
The Turning Point Hustler is an aluminum prop said to deliver SS like performance.
There may be a selector switch on the back of the tach.Note its position and operate it a few times to clean the contacts.

 

[rebel16fisherman]

Re: Stainless Steel Prop for 1990 2Cyl 40hp Johnson

I have been doing some more research in my spare time and was wondering if anyone has heard anything goo about the 3 blade Solas Amita propeller?

 

[steelespike]

Re: Stainless Steel Prop for 1990 2Cyl 40hp Johnson

The Solas Amita has a good reputation for predictability and sound performance.
Have you been able to confirm your tach?