Stainless Steel Prop

[Sakakawea]

I currently have a 90 hp 2 stroke yamaha tiller with the factory prop on it. Is there a need to go with the stainless steel prop. What would be the major advantages of going to a stainless steel prop? My first boat so I am kind of new to the new prop scene. Thanks

[walleyejohn]

Are you unhappy in any way with the performance of your boat now?
Generally speaking, a comparative SS prop will probably provide a bit more top-end and some additional efficiencies to aluminum.
The metal does not flex (as much) and so it's more efficient, but it costs more.
If you are operating in shallow water with many obstacles (rocks, logs, etc) aluminum may be right for you, since you run a greater risk of striking bottom with your prop.
If you're in deep water or with a very soft bottom, you may find benefit to boating with a SS prop.

But SS props are not all rosy.
On some engines, they cause a "clunk" into gear (due to the additional weight/mass of the prop).
If you trailer your boat, a SS prop is at greater risk of being stolen in a parking lot; because of it's higher value.
They're priced at a premium for a reason, and it isn't completely tied to the price of raw materials.

Good Luck,
walleyejohn

[ffishman]

I have one on my 150merc. But, with the cost of them, I don't think its worth it on a 90hp. I don't think you will notice any difference, except you wallet will be lighter.

[hondo]

If you're happy with the way your boat runs and the performance you're getting, then there's no reason to change. If there's some aspect of your boat's performance or handling that you're trying to improve then a stainless prop might help you, but it's always a trade-off ----- for everything you gain in one area, you'll give up something in another area. For example you might increase holeshot but lose top end speed, or might gain speed with a light boat but lose overall performance with a normal load, etc.

I also agree that with a 90 hp motor you don't have enough HP to really take advantage of some of the benefits you can get with stainless.

[propmann]

I also agree that with a 90 hp motor you don't have enough HP to really take advantage of some of the benefits you can get with stainless.

I don't agree with you. If you get set up with the right prop you'll see a big improvements

[Manxfishing]

I put a SS on My 90 hp (F90 Yamaha) and I noticed the difference

I even went down a pitch and still picked up top end and the holeshot was night and day
My thoughts are, there's a better cup on a good SS over the alum
I notice allot less slip

[propmann]

I put a SS on My 90 hp (F90 Yamaha) and I noticed the difference

I even went down a pitch and still picked up top end and the holeshot was night and day
My thoughts are, there's a better cup on a good SS over the alum
I notice allot less slip

exactly right here that all time, lot of people say its like putting a new bigger motor on.

[staylor]

...on a tiller motor you normally won't gain much with a SS prop- other than clunking when you go into gear and oftentimes more force required on the tiller to steer. This is due to the extra weight of the SS and the fact that they usually run more blade rake angle than the aluminum props. Speed wise, if your boat carries the bow OK then you will be lucky to gain more than 1 mph over the proper aluminum prop. If you want to experiment, get a spare aluminum in the right pitch and have a prop shop add some cup to it- in fact you can add the same amount of cup as a high dollar stainless prop for about $40. In general, if the boat rides OK and runs less than 50 mph, then there is very little to be gained from SS- other than the weight loss in your wallet. Blade flex in an aluminum prop only is an issue if the prop is run partially surfaced from having the engine lifted up 3-4 holes on the transom. When running submerged, all the blade flex does is to give you the effect of slightly less pitch. If you are running in the correct rpm range at top end then you have already compensated for the blade flex. My prop box in the basement presently has 8 high dollar SS props for my big rig, and 4 aluminum props for my tiller rig, so I'm giving you my unbiased opinion.
Doug

[KP]

I have a 70 HP motor on my rig and have experienced tremendous gains with a stainless prop. The main benefit is better lift which resulted in vastly improved mid RPM cruise and better fuel economy. Other benefits are better hole shot, better acceleration, better top speed, and less blow out in turns. A stainless prop will also make your steering easier and more responsive, not more difficult. The weight of a stainless prop is insignificant under power when you consider all the torque thrust of a motor.

However, the key to good stainless performance is first getting your rig setup for best performance with the correct pitch aluminum prop that allows your motor to rev in the upper end of the Max WOT throttle range with one person in the boat, a half tank of fuel, and light load. That may include raising or lowering the motor and better weight distribution like relocating batteries and/or anchor(s). Don't assume the dealer set you up with the correct pitch prop or even mounted your motor at the optimum height. Often that is not the case. Once you have those setup issues dialed in, you'll be better prepared to purchase a stainless prop with the correct pitch and blade geometry for the performance improvement you are seeking.

There are too many people that jump right into a stainless prop without taking these steps and are disappointed with the result. Same thing for people that buy hydrofoils or trim tabs to cure problems that may be better resolved by relocating weight, raising the motor, or getting the correct picth prop.

[Manxfishing]

Kp
I'll agree that the SS does give me better bow lift
But at the same time Staylor is right that there is an increased force required in steering a tiller
The SS has more bite thus the increased in the steering

My thoughts are
The alum props are a general design that fit a very wide range of conditions
And there a truth to not seeing the benefit of the SS not flexing vs. an alum on a lower hp motor
But the right SS with have benefits of a better design and there allot more durable then an alum
There used to fine tune the boat for that last bit of performance

[FinsNFeet]

I had a 1992 85 HP Evinrude V4 Tiller on a 1890 Pro V Gary Roach Edition Lund. The alumin. prop I was getting 34 MPH (GPS) @ 5600 RPM @ WOT. Switched to a Stiletto SS 13 1/4 X 15 prop ( Was told it would actually measure to a 17 pitch). My hole shot improved considerably my RPM's lowered to 5300 RPM's @ WOT and she did handle better in the turns. I also lost 1.5 MPH GPS. My MPG did seem to go up. I didn't have a fuel flow then so I can not give you any numbers . I have since repowered to a 90 HP E-Tech tiller. I am getting about the same MPH some days slower and some faster. Not a lot just 1 MPH + or - . My RPM's @ WOT are only 4950. I have to get my tach checked on this new motor before I start changing things. If the tach is correct I will be putting the alumin prop back on and see what numbers I get from her then. I wouldn't say it was money poorly spent, but I don't know if I would rush to do it again either. I did notice improvemnet in some areas and like it was said a loss in others. The most noticable improvement for me was the hole shot. It was a considerable improvement, I never put a stop watch to her but she does get up and go. Just my experience with the change over. :huh:

[KP]

What diameter and pitch was the aluminum prop? I'm not familiar with a 15 pitch stainless that measures like a 17 pitch?

[propmann]

I had a 1992 85 HP Evinrude V4 Tiller on a 1890 Pro V Gary Roach Edition Lund. The alumin. prop I was getting 34 MPH (GPS) @ 5600 RPM @ WOT. Switched to a Stiletto SS 13 1/4 X 15 prop ( Was told it would actually measure to a 17 pitch). My hole shot improved considerably my RPM's lowered to 5300 RPM's @ WOT and she did handle better in the turns. I also lost 1.5 MPH GPS. My MPG did seem to go up. I didn't have a fuel flow then so I can not give you any numbers . I have since repowered to a 90 HP E-Tech tiller. I am getting about the same MPH some days slower and some faster. Not a lot just 1 MPH + or - . My RPM's @ WOT are only 4950. I have to get my tach checked on this new motor before I start changing things. If the tach is correct I will be putting the alumin prop back on and see what numbers I get from her then. I wouldn't say it was money poorly spent, but I don't know if I would rush to do it again either. I did notice improvemnet in some areas and like it was said a loss in others. The most noticable improvement for me was the hole shot. It was a considerable improvement, I never put a stop watch to her but she does get up and go. Just my experience with the change over. :huh:

The problem was you should of been sold the 15 pitch and it would of kept your rpms up and you would of gain speed. On your etec you definitely need the 15 pitch then you'll be running around the 5400 range

[FinsNFeet]

I was happy the way the prop performed on the older V4 85HP motor, I would have thought that just the increase in the 5 ponies I would have realized better numbers with the SS. Are the E-Techs not putting out the torque that the older motors put out. I have heard that the 90's are really 70's just juiced up by the computer. Is that part of the problem? Nothing else changed on the boat to add weight I actually removed the 9.9 Mercury kicker that I had on it. :huh:

[Hot Runr Guy]

I was happy the way the prop performed on the older V4 85HP motor, I would have thought that just the increase in the 5 ponies I would have realized better numbers with the SS. Are the E-Techs not putting out the torque that the older motors put out. I have heard that the 90's are really 70's just juiced up by the computer. Is that part of the problem? Nothing else changed on the boat to add weight I actually removed the 9.9 Mercury kicker that I had on it. :huh:
Keep in mind that that V-4 was a 99.5 in3 motor, vs your current 79.1 in3. Hard to beat cubic inches for raw torque. But, you gotta admit, that EFI/DI ease of starting is kinda nice.
HRG

[FinsNFeet]

Everything about the motor I like. The lack of noise going down the lake. No smoke, she starts when I want her to with out choking the living day lights out of her. no breakin period, everything. I'll stop before I sound like a commercial. I was a little disappointed in the torque issue, I didn't realize the difference in the cubic inches of the motor I assumed it would be bigger 85 to 90. There goes that assume rule .:exactly:

[staylor]

Very few modern motors in the 80- 120 hp range can equal the torque of the old OMC V-4, affectionately called the "Fat Four" by the old motor lovers of the AOMCI. When the motor originally came out in 1957 it was rated at only 50 hp, from a displacement of 89.7 cubic inches- if my memory is correct. They were punched out and altered over the years in many ways, ending up being replaced with the OMC V-4 Loopers. All of these V-4 motors were real stump pullers compared to the competition. They also tended to smoke a lot and chew up lots of gasoline compared to the motors of today- especially the early ones, running 24 to 1 oil mix. When I traded my 1984 V-4 140 in on a 175 OMC V-6 back in 1989 or so, I called the OMC factory to complain that the darned V-6 wouldn't idle below about 750 rpm which made it a lousy slow troller. The fellow I talked to asked what I had been running previously and I told him a V-4 140 with the idle slowed down to 500 rpm in gear. He laughed and told me that I would never get the big V-6 to run anywhere near as smooth and slow as the old V-4. he reminded me that the V-4 was designed for boats that only had 1 motor on them, and it was expected to go fast, pull skiers, and troll slow.
Doug

[FinsNFeet]

The old V4 was a beast. I do not tow any skiers but when you gave her some gas you could feel the power. This new E tech does perform well and so far I would recommend it to any friend. I wish the boat wasn't rated 90 HP max. Which to this day I do not understand. I was told that the Pro V hull was a ProV hull. If this same hull had a sterring wheel it would have a much higher rating. ( So I was told). I would love to feel what a 150 HP tiller would do.:driver: