Prop erosion back side on modded everude 15hp 8p 6600rpm

[Sinkingfast]

Been working on this project since fall of 2014. 1232 jon with a 1976 15hp. Internal cleanup with my die grinder. No port changes. Solas 4 blade 8p prop. Fantastic out of the hole for a 13cu motor. I'm old so I am at half throttle or less most of the time. The boat is a lot of fun. Issue is I pulled out the boat for a local trip to another water hole and found erosion on back side of the prop, half inch from trailing edge, half inch long by 1/8 wide, 3/4inch from tip on all 4 blades. I have spent 3 or so hours reading but no fixes to speak of. I think the leading edge is too blunt causing bubbles and then collapsing at the erosion spot. Maybe sharpen the leading edge? Anybody with experience on prop erosion?

 

[tomme boy]

Make it run in cleaner water. Put a jack plate on it to get it back farther from the boat to run in cleaner water.

I tried that prop on my 15 Suzuki and it would not even get boat on plane. The blades are just too small.

 

[Pappy]

Your theory is correct! Congrats on doing your homework and understanding it.
Unfortunately....you may end up changing to a different design propeller with less vacuum behind the working side of the blade.
That is not much pitch for that boat/engine. I would think a 10" pitch prop or better for that boat.

 

[Sinkingfast]

Just got back from Sacandaga Reservoir and it was very nice. Not a lot of water though. Just tooled around and no further erosion. I have a Solas 4blade 10p with no erosion but only 5700rpm. I will say 6600rpm makes me nervous. Sounds like its screaming its guts out. The 4 blade works better than the oem 3 blade for stern lift..its quite noticeable.

Mr. tomme boy what prop did you finally go for on your Zuke?

 

[tomme boy]

PowerTech SRT4 in 10 pitch. It grabs and holds water like you would not believe!

 

[whitetailhntr]

PowerTech SRT4 in 10 pitch. It grabs and holds water like you would not believe!

Which size motor is that on?

 

[Sinkingfast]

Well I sharpened my 10p and picked up 100 rpm according to my tinytach. But I miss the explosiveness of the 8p :lol:

I filled in the cav spots with JB and did a sharpening job on the 8p, hoping for the JB to still be there after testing.

5500 to 6500 is the rpm range, the 6600 is with nothing in the boat including safety items. When I add anchor, box of stuff, vests, 6 gallons gas it drops to 6400 rpm with 8p.

Of course my China knockoff tinytach is stuck at 3550 rpm now. I guess 10 bucks including shipping for it was not prudent. My real one from 7 years ago still works if I could replace the battery.

 

[tomme boy]

15 Suzuki

 

[Sinkingfast]

Well, the JB lasted 4 minutes at wot on the 4blade8p. So I took the 4blade 10p and removed the trailing edge cup as a last resort to use the 10p. I wasn't sure if the cup was paint sag. The 10p now brought my rpm up another 200 and the boat is spot on now.

 

[Sinkingfast]

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