Prop cavitation/ventilation damage?

[slowridertx]

Have a 2009 Honda 225- great engine- smooth on our 2010 Avalon 27' Ambassador. Built great, great engineering. Came with an Apollo stainless 3 blade 14 1/4 x 17" prop. Ran fine. Dealer provided a backup Apollo 14 3/8 x 15" to try for best performance due to some customization work that added weight and weight distribution. This weekend put the 15" on by the book and have replaced many props- no problem. Took boat out for series of WOT (5,000RPM) , 75%, 50% throttle runs and trim settings (I'm analytical). On first run at barely 2500RPM, felt a little flutter but went away. Ran for about five minutes to get momentum and then was going to WOT but before that at 4,000RPM, had massive cavitation/ventilation spin out. We stopped moving, engine spun up and I cut the throttle instantly. Kept engine in idle to cool her off for a minute then re-engaged up to slow 6kt cruise back to dock to ensure things going okay. Then in 10 minutes, heard another spin out/cavitation episode and prop stopped turning. Ended up having to get towed! Have had Merc and Volvo Penta engines- no problems. What on earth could a simple prop change do?? Prop wasn't torqued wrong, lubed, thrust washer fine. Hoping to God that Honda has a good destructing gear assembly so my main shaft is fine and just need some sort of prop shaft gear work. Should be (better be!) a warranty covered issue. Maybe prop was machined off spec? Appreciate group's knowledge base so I can have fair/balanced discussion with dealer, Honda, Apollo. P.S. Boat just delivered on July 4th and the 17" prop had no problems- just seemed like I was burning a lot of gas just for slow cruising (we aren't big skiiers or tubers- just sunset cruises.) Thanks !!! Slow Rider in Texas.

 

[steelespike]

Re: Prop cavitation/ventilation damage?

Speaking generically your prop hub may have failed prematurely and you may have experienced simple spun hub to the point of comeplete failure.As far as fuel use the 225 will burn about 22 gph (gallons per hour) at wot.I your running at a arbitrary cruising speed keep in mind the best speed could be from just on plane to about 1,000 rpm higher.experimentation or a flow meter are about the only way to tell
the ideal cruising speed.

 

[slowridertx]

Re: Prop cavitation/ventilation damage?

Thank you for your comments and also advice for future fuel/speed management- once we get her back I'll put that in action. If anyone has any questions about Avalon Ambassadors- would be happy to be a source- we love that boat and have a top-notch dealer- the best we've ever encountered anywhere- period. We are just sorry this happened on their watch- they've spoiled us and hate this problem being on their plate. Have a great one and I'll share with the forum what we find out once the Honda comes out of surgery.