size help... switching from aluminum to stainless

[Jasonfishing]

Hi, new member looking for any suggestions and thank you in advance for the help. I have a 2000 Hydra sports center console with a 2000 90 horsepower 2-stroke Johnson. Currently I have an aluminum prop, it's the original that came with the boat 14 x 17 OEM prop. The prop works great, but it's a little dinged up and I have a friend who has a prop for sale for $80, brand new in the box stainless steel Michigan wheel 15 X 17. Model 013044, it was their spare for a boat they no longer have, least to say the $450 prop for next to nothing so if it'll work on my boat I'll get it. My wide open throttle on normal load is about 5100 RPM at about 41 miles per hour with the aluminum prop any suggestions? Will this prop work with same performance? Not looking to dump three or four hundred dollars on a stainless, thanks for any suggestions

 

[Sea Rider]

Need to know as a starter min-max wot rpm range for that engine. If possible test new prop being offered, will know if that's the prop your combo needs to run inside middle to max wot rpm range as factory stated.

Running middle rpm achieves a slight faster top end speed, hole shot will suffer a bit, runing at max wot rpm range, hole shot will be increased with slight top end speed loss. Which one you prefer, it's entirely up to you..

Happy Boating

 

[89retta]

For $80 buy it and try it. If you don't like it put it up for sale. Its not like you're spending lots for it.

 

[Texasmark]

For $80 buy it and try it. If you don't like it put it up for sale. Its not like you're spending lots for it.

Right answer. Every thing about a prop is pure speculation until you run it. On where your rpms are when you run it, depends on how you use your boat. Propping for water toys vs speed with a light load are two ends of the spectrum. One prop can't do both jobs so you have to pick one and when in the other, just live with it.

I liked to prop at the upper limit of the mfgrs. max rpms when doing what I do most. If that's water toys just keep your rpms under control when running light if they start getting too high.

 

[Jasonfishing]

It's my understanding that wot RPMs should be between 4500 and 5500. Presently I am at 51 or 5200 with my current crop, but I cruise out of about 4500

 

[Jasonfishing]

I guess my real question is, am I going to notice any difference when switching from aluminum to stainless if it is the exact same size prop and pitch? And if so what would that difference be more speed, less speed, an undesired change in RPMs at wot, don't really know what to expect as I've only ever had this problem iboats

 

[Sea Rider]

That's the same question was asking myself running 2 same diam/pitch props, one being alum the other SS. The answer is : will need to test them both at full wot and as currently loaded on flat calm, non windy water cond. I guess the SS being heavier will spin less consequently will drop some wot rpm, how much, impossible to tell..

If engine would run at max 5.5 K wot rpm range, you can go cruising at the rpm you like most. Theoretically will need to drop one pitch for engine to rev to full wot rpm range, will better slightly your hole shot, but that's fine tuning towards the max 5.5 K rpm factory stated.

Happy Boating

 

[yamatech43]

Excellent points from many, one more that will help in this case I believe and save you the trouble of wasting the time to buy and then sell this prop is a handy rule of thumb....you say you can get max of 5100 rpm, which to me on that 90 is getting a little low for durability.....a stainless prop of the SAME size as an aluminum will COST you 200 RPM in this size range....and you can't afford to lose any from 5100 rpm max. You can't possibly go stainless AND increase the diameter unless you just hate that engine and have to kill it.

 

[Sea Rider]

What if both props are same 17 diam and pitch, one being alum the other SS. Is prop diam or weight or both to take into account for engine to achieve -200 wot rpm difference ? Personally will never go for SS props as like OEM alum factory ones which performs quite well for my applications.

Happy Boating

 

[dingbat]

What if both props are same 17 diam and pitch, one being alum the other SS. Is prop diam or weight or both to take into account for engine to achieve -200 wot rpm difference ? Personally will never go for SS props as like OEM alum factory ones which performs quite well for my applications.

Happy Boating

stainless props tend to have more cup than aluminum. More lift, less slip

 

[ahicks]

I'm with texasmark here. If your original is banged up and you can get this prop, which is the same size, for 80. it's a good deal. Beyond that, unless both the original and the new prop have the exact same profile and prop blade shape (not likely), minor performance differences would be no surprise, but you would have to run it to notice.

That said, props (stainless or alum.) can be tweaked by a good prop rebuilder to dial them in to your exact rpm requirements. Point being, if this new prop doesn't suit your needs as well as what you have now, it can be repitched or cupped to meet them perfectly very reasonably. You could still be into it for less than the price of a quality alum. prop....

 

[jimmbo]

Stainless Steel props weigh a lot more than Aluminum so they do take more power to spin up. The weight increase varies depending on how close the SS prop copies the AL, or being much stronger , are the blades thinner? Thinner blades are more efficient so that will work in SS favor. Being stronger also allows for better blade shapes. The extra strength of the SS becomes a Liability when impacts occur. AL props will bend/break blades off far easier than SS, which bends and tears, but transfers more stress to the propshaft/gears/driveshaft. The extra mass of the SS prop also places more stress on the clutch dog when shifts occur. But it is each boaters choice, I do use SS and have had to replace propshafts after impacts. It wasn't
even a High Speed impact, about 20mph.

 

[Texasmark]

It's my understanding that wot RPMs should be between 4500 and 5500. Presently I am at 51 or 5200 with my current crop, but I cruise out of about 4500

Don't worry about cruising. WOT with your most often run load is where you establish the benchmark. The rest is just what you do with what you have benchmarked.

 

[Texasmark]

stainless props tend to have more cup than aluminum. More lift, less slip

........aaaaah.....Turning Point Hustler has everything but the metal.....high rake progressive pitch, cupped, ports, and thinner blades than most alum, but not as thin as SS.....and the last one I bought on Iboats was 99 bucks.

 

[Faztbullet]

I don't think you can put a 15" diameter on a V-4 unit(4.25")gearcase

 

[dingbat]

........aaaaah.....Turning Point Hustler has everything but the metal.....high rake progressive pitch, cupped, ports, and thinner blades than most alum, but not as thin as SS.....and the last one I bought on Iboats was 99 bucks.

For the heck of it, I entered my data into Turning Point prop calculator and it spit out of list of recommend props, all stainless. (Express)

I think I'll keep my Enertia

 

[Texasmark]

For the heck of it, I entered my data into Turning Point prop calculator and it spit out of list of recommend props, all stainless. (Express)

I think I'll keep my Enertia

I use "go-fast.com" calculator. Never tried nor knew of the TPPC.

 

[Bikestdy]

I use "go-fast.com" calculator. Never tried nor knew of the TPPC.

I think he means the prop selector tool, not calculator.

 

[Texasmark]

I think he means the prop selector tool, not calculator.

Can't comment. Haven't "been there".