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I've been running a Stiletto SS 13.25x17 on my e-tec 90 for about 25 hours and there are pits on the base of each blade. This is run in fresh water and turns 5200rpm at wot. I had a 13.25x15 on this enging for a few years and had no problems.

Any ideas?

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If they are not corrosion then the pits are cavitation burns from the vacuum that is formed on the blade as it cavitates, you may have the wrong pitch on there for your boat.

Any nicks on the prop?? Near the pits?

Check this out.

http://sites.mercurymarine.com/portal...ema=PORTAL

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brand new prop, no nicks or dings. Pits are distributed evenly on all 3 blades at the base.

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I agree, that sounds like cavitation. I am surprised to hear that cavitation could occur with that propeller/motor combination; I have never seen that before.

Can you provide details of how the motor is rigged?

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I'm kinda of reaching here...but could it be that the paint wasn't properly applied to the prop from the factory? Maybe if you sand it down, prime and re-paint it and then run the prop for a few hours and see what happens.

I had a similar issue happen to me back in the early 90's on a prop and what I mentioned above was my solution. I know props and paint have come a long way since then, but I just wanted to toss that train of thought logic at ya.

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There is no paint on a polished stainless steel propeller.

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My bad....not familiar with the stiletto prop.

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Tom,
Rigged the same as the 15". Setback 6" and about 2-3" above the keel. Again, max rpm is 5200. I'll try to get some pictures.

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That is VERY weird.

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I've posted 2 pictures at the end of my Personal page. Please check it out.

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Hi, What was the wot with the other prop? Why did you change to the 17" pitch?? The rpm you're showing is on the lower side of the chart. How much weight do you ADD when you're out, ice, fishing tackle, people, etc.? I'll bet the oil/gas consumption went up as well with the 17" pitch wheel. Sounds to me like the engine is working harder now to get where you're going. And that is cavitation on the base of the blades. Is the other wheel stainless.

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4800 to 5200 is the sweet spot per the e-tec charts for the 90hp. I was running as high as 5700 with the 15". No difference in weight or fuel usage that is measurable.

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All i see is a little rust.. sorry i can't see any pitting.

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Yea, I keep forgetting the 90 hp is a inline 3 cyl. engine. So the rpm is where it should be.

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Terry -- I agree, the photos do not look like cavitation at all, just a little rust which is very common. I wouldn't worry about it.

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[ Eli -- Welocme to Whaler Central.

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