Evinrude 25 - Spun Prop?

LaqueRatt

Chief Petty Officer
Joined
Jun 27, 2022
Messages
444
Got my new motor running nicely in the barrel. Had it out on the lake for the first time. All seemed good. A few WOT blasts, slowing to idle in between for fine tuning. Took off again, running at about 3/4 throttle. All of a sudden motor revs way up, boat slows down. Wouldn't move except at just above idle, but at least we were able to limp back in.

Last summer had the same thing happen with the Fastwin 18, but that hub was absolutely shredded. No doubt the prop was bad. Took the prop off the new motor and it "looks" fine, but I'm thinking that doesn't mean it is. I just can't think of anything else it could be. What do you guys think? Should I just buy a new prop?

Attaching pics of this prop along with the 18 to show how munched up the 18 was in comparison.
 

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  • Prop Hub.jpg
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  • Fastwin Prop Damage 04.jpg
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  • Fastwin Prop Damage 05.jpg
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F_R

Supreme Mariner
Joined
Jul 7, 2006
Messages
28,224
Easy to tell. Make a mark on the prop nut, or use the cotter pin as a mark. Make another mark on the prop, aligned with the first mark. Run motor till the suspected slippage occurs. Stop motor and check the marks. If no longer aligned, it slipped.
 

LaqueRatt

Chief Petty Officer
Joined
Jun 27, 2022
Messages
444
Will that work in a barrel though? Trying to avoid launch fees and the hassle of launching and retrieval. If it could be nothing but a spun prop I might as well just replace it. Could it be something else? I'm thinking anything else and that boat would be dead in the water. Maybe I'm wrong. I have a lot to learn.
 

F_R

Supreme Mariner
Joined
Jul 7, 2006
Messages
28,224
95% chance it is the hub. That leaves 5% for cavitation, etc.
 

LaqueRatt

Chief Petty Officer
Joined
Jun 27, 2022
Messages
444
That is my take on it as well. I'm just surprised the hub isn't munched. At first it did seem like cavitation, like the prop was out of water, but afterwards it wouldn't move at all except at low RPMs. Which is what it's supposed to do right? I was clear to the other end of the lake so was happy to get back under power. Would have been a long trip back with the troller and no telling if the battery would last that long.

Guess I'll go ahead and see about ordering a new prop. If anyone else wants to weigh in first, I'd greatly appreciate it.
 
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