Whats going on here?

[Juzza]

Could someone please explain why this is occurring and how do i stop it.
60HP Yam 4 stroke 4.35 Wildcat, no performance isssues 80hrs.

[Bash]

Hey mate,
Have the same thing happening to my 40hp yamaha... I'll try to get some pics for you soon. Check your anodes maybe mate. I was told it has something to do when driving and the way the water hits the propeller.

[Ian Sewell]

It is cavitation. Could be any number of causes. Motor could be too high, wrong prop pitch, overpowered, trimming out too far when running, turning with motor trimmed up and the list goes on... Yes most of these will cause ventilation which will then lead to cavitation.

[Juzza]

I read that cavitation damage will appear on the opposite (front) side of the prop so I ruled out cavitation is that correct?

[walloper]

I had a 25 HP Yammy that had similar issues at the prop. I purchased the motor and had it set up correctly ???
The fact that mine didn't have electric tilt and trim, it was tiller steer, may have ment a notch either side wasn't right for my boat.

[aussiematrix]

Guys I was looking the other day at my brand new yamaha prop that has seen the water only 4 times on my 60hp and noticed that a section of paint was missing in the same point as in photo above. Its only a small section only about 4mm long and its only on one blade I thought is was just a painting issue from the factory. Will keep a eye on prop and this thread.

Aussiematrix

[Rooney1997]

Scratch that last comment made by myself.

[Ian Sewell]

It could be just from twisting the throttle hard while the boat stands still. Certainly does not look like a serious issue. If it gets bad it will make bigger holes which can eventually go straight through your prop.

Keep an eye on it and if you are really concerned about it you could always get a stainless prop which will be a nicer shape and probably not cavitate at all.

Cavitation usually happens on the face of the blades (but not always).

[Kyle101]

Originally Posted by Ian Sewell

It could be just from twisting the throttle hard while the boat stands still. Certainly does not look like a serious issue. If it gets bad it will make bigger holes which can eventually go straight through your prop.

Keep an eye on it and if you are really concerned about it you could always get a stainless prop which will be a nicer shape and probably not cavitate at all.

Cavitation usually happens on the face of the blades (but not always).

I had a similar issue on my old boat and the mechanic had the same conclusion as you Sewelly, replaced the prop to stainless with a different pitch and the issue seemed to of went away. Have since sold the boat so I can't provide any further details sorry mate.

But certainly get it checked out, hopefully its nothing but prevention is the best way!

[thecheif]

its prop burn it can be from one or all of these cavitation ,over trim ,over rev usually comes from over trim use a stainless steel prop and youll never see it again

[Flyman1]

I am sure Solas would be interested in your pics. Give them a call to discuss and if necessary send them the pics also. I am sure they will be able to advise what the problem and solution is.

Has anyone seen the movie on the net on cavitation and how water dissolves a stainless steel prop?? They fast forwarded it and its crazy nuts!!!

[thecheif]

yeh but its allso bullshit water dosnt dissolve stainless steel it might sharpren it a bit but due to its hardness and the coolness of water thats abouts it i personally have had many props custom for one boat and i change them like shoes depending on what sport im about to play . my current projrect is a 7.2 genesis craft with twin 175 suzuki 4 strokes full fly by wire and counter rotating i reckon once its proped up right 60 knts with a full load =fads in 20mins if your brave so if anyone wants more freindly info on prop help pm me any time this will be the third of many boats i have at the moment,and my one aim is engineering them to perfection

Originally Posted by thecheif

yeh but its allso bullshit water dosnt dissolve stainless steel it might sharpren it a bit but due to its hardness and the coolness of water thats abouts it i personally have had many props custom for one boat and i change them like shoes depending on what sport im about to play . my current projrect is a 7.2 genesis craft with twin 175 suzuki 4 strokes full fly by wire and counter rotating i reckon once its proped up right 60 knts with a full load =fads in 20mins if your brave so if anyone wants more freindly info on prop help pm me any time this will be the third of many boats i have at the moment,and my one aim is engineering them to perfection

"bullshit"

Also love the grammar - reads well.