Which SS prop for 90HP Johnson?

[zenwriter]

My 90 HP Johnson 2-stroke, year 2000, has an aluminum prop, number 177131, 14 x 17.

It is pushing a Sea Hunt Triton 173, year 2000, 1300 pounds dry weight. Engine revs to around 5800-6000 RPM at WOT. I usually cruise in the 20-25 MPH range with about half a tank of gas and 1-3 people. Also do a lot of trolling at 4 mph or less.

I'd like to switch to a stainless steel prop. for whatever benefits it can deliver. Can anyone suggest what I would need?

Tom

 

[SkiDad]

Re: Which SS prop for 90HP Johnson?

I'm not sure what your goal is - it's hard to say what stainless brand to get, but your rpm is pretty good - maybe a tad high. If that rpm is with a full load and 3 guys I would consider a 19 pitch 3 blade - maybe look at Solas props. You do have some room if you need more speed to go with a 19 pitch prop and still be in the correct range - it depends on your goal.

 

[steelespike]

Re: Which SS prop for 90HP Johnson?

If you give us your present wot rpm and gps speed it will help determine how well your present performance is.
While a ss prop can improve overall performance .
A ss prop will cost about 3 times that of an aluminum and there are al props that can deliver close to ss performance.

 

[jestor68]

Re: Which SS prop for 90HP Johnson?

With a max rpm of 5500, it appears that a 19 pitch might be in your future.

 

[zenwriter]

Re: Which SS prop for 90HP Johnson?

14 x 17 aluminum prop, 90 HP Johnson 2-stroke (year 2K), 1400-lb. hull dry weight, WOT is approx. 5800 RPM at 34 MPH on the GPS.

Is this information helpful?

 

[SkiDad]

Re: Which SS prop for 90HP Johnson?

With that info I would say something is not right. I would expect at least 40 mph with the 17 pitch prop. You are showing 27% slip. Should be more like 10%. Maybe you engine is too high on the transom.

 

[steelespike]

Re: Which SS prop for 90HP Johnson?

14 x 17 aluminum prop, 90 HP Johnson 2-stroke (year 2K), 1400-lb. hull dry weight, WOT is approx. 5800 RPM at 34 MPH on the GPS.

Is this information helpful?

At 27% slip I wonder if the tach may be wrong.Perhaps you can borrow or rent a shop tach to check.
Is your prop worn or damaged?Is your gps set for mph.
Are you running against a current?
Is there a Hydrofoil on the motor?

 

[etracer68]

Re: Which SS prop for 90HP Johnson?

Pictures of the prop, bottom, cav plt measurement from bottom. One thing you can do is, reset the pulse on the back of the tach. I think 6 is where it should be, rotate it back and forth a few times, then put it back to 6.

My opinon on SS props, is money out of pocket, unless your looking for performance, that really doesnt put money back in your pocket.

 

[zenwriter]

Re: Which SS prop for 90HP Johnson?

Will have to check out the cav. plate measurement and photo: I notice the engine is mounted in the 2nd hole from the top -- there are two holes below this.

The engine and boat are year 2000, and I can't find a performance report for the 90HP Johnson on the Sea Hunt Triton 172. But I did find one for 1991 with a Yamaha 90HP 2 stroke, model 90TLRA.

Prop is 13.25 x 17 (mine is 14 x 17), engine is mounted in the no. 2 hole (same as mine). With 2 people and 23 gal of fuel, WOT was 5300 RPM and speed was 38.7 MPH.

I get around 34 MPH at what I believe is higher RPM, and I have added a t-top. Spec for the Johnson is up to 5800 RPM and that is what my tach showed.

Am having my OMC prop reconditioned by Bossler & Sweezey in Bellport, NY. Not sure if getting a new prop is worth a few MPH in top speed. But I do wonder about gas mileage -- I troll a lot and the engine seems pretty thirsty.

 

[steelespike]

Re: Which SS prop for 90HP Johnson?

A 90 will use about .10 of a gallon per hour at 700 rpm.
At wot it will use about 9 gph whether pushing a house boat or a runabout.
At 34mph thats about 3.77 mpg.

 

[hwsiii]

Re: Which SS prop for 90HP Johnson?

At 27% slip I wonder if the tach may be wrong.Perhaps you can borrow or rent a shop tach to check.
Is your prop worn or damaged?Is your gps set for mph.
Are you running against a current?
Is there a Hydrofoil on the motor?

As Spike mentions, somewhere in those numbers is a big problem, as there is no way that particular boat should have a prop slip of 27%, and you should be getting more speed than what you are right now.

Adding to spikes and etracer68s questions what make and model of aluminum prop are you using at this time.

H

 

[zenwriter]

Re: Which SS prop for 90HP Johnson?

The prop is OMC, model # 177131, 14 x 17. I would guess it's the original prop that came on the engine, Johnson 90 HP, year 2000.

 

[hwsiii]

Re: Which SS prop for 90HP Johnson?

zenwriter " I get around 34 MPH at what I believe is higher RPM, and I have added a t-top. Spec for the Johnson is up to 5800 RPM and that is what my tach showed.

Am having my OMC prop reconditioned by Bossler & Sweezey in Bellport, NY. Not sure if getting a new prop is worth a few MPH in top speed. But I do wonder about gas mileage -- I troll a lot and the engine seems pretty thirsty. "

Does that motor have the V4 gear case or the V6 gear case.

When you get your prop back and if it does not increase your speed by at least 4 mph then you need to look at purchasing another prop. I have seen many smaller boats after installing a T- top lose 3 to 5 mph easily depending on the direction of the wind and its speed, thus increasing prop slip to numbers that are too high and wasting fuel.

I am positive we can increase your top speed by at least 5 mph with a new prop for about $ 125, if your repaired prop doesn't do it.

H

 

[zenwriter]

Re: Which SS prop for 90HP Johnson?

Thanks, will check out top speed of the new prop. My 90HP Johnson is a V4. I also have a new tach that I want to run side-by-side with my current one to see if the RPMs are correct. Engine runs great so if the RPMs are low, I will look at the throttle cable.

 

[zenwriter]

Re: Which SS prop for 90HP Johnson?

BTW, I checked on the gearcase. Engine is J90VLSSE. Here is the gearcase spec:

http://www.evinrudeonlineparts.com/...ARCASE_-_90_AND_115_PX,_VX_MODELS/29439/57633

 

[etracer68]

Re: Which SS prop for 90HP Johnson?

The fast way to tell if you have a V6 gear case is , the prop, will be a 15 spline, were as a standard V4 gear case is 13 spline. And in general a V4 prop will generally come in an 13inch dia, more so then an 14 inch dia. Most V4s are under 13.5 in dia. Your more conserned with pitch, but, maybe the larger dia isnt cupped.

 

[zenwriter]

Re: Which SS prop for 90HP Johnson?

definitely 13 spline on the prop...will have to look into the cupped issue...

 

[1FASTLASER]

Re: Which SS prop for 90HP Johnson?

I run a 90 hp Evinrude on a Tidecraft bass boat that measures 16 1/2' and weighs approx 1100lbs loaded for a tourney. I run a original Raker 13 1/2x20 with Excellant results. I am not familiar with your hull but the speed and rpms u say u r running do not come out right. You should at least be in the low 40's as I run loaded 48. I would DEFINATELY be looking at the tach as possibly reading incorrect and I suspect very much that the 14" diameter u have is to big diameter wise