Alum Prop Flex

[StriperChaser]

I saw a topic posted about worn props and made me think about mine. My original prop from 1997 appears to be in good shape although a little paint worn off. I know aluminum props will flex to some degree compared to SS but do alum props flex any more after several years of use?

 

[Spidybot]

Re: Alum Prop Flex

If the prop hasn't had any damages it will perform as new even after several years.<br /><br />Do you experience problems with the one you have?<br /><br />What make and model is it, what is your boat and how many rpm do you reach at WOT?

 

[StriperChaser]

Re: Alum Prop Flex

Thanks for the response. It's a Johnson 112 on a 17' Seaswirl CC. Engine seems to run good, with new plugs, decarb, carb rebuild within the last year. The commpression is good and runs 4900 RPM @ WOT. All that said, it just does'nt plane off nearly as quick as it used too and my top speed is lower. This is the longest I have ever used the same prop without knocking a blade off on something.

 

[Dhadley]

Re: Alum Prop Flex

At 4900 (top rpm) you are putting that motor in an awful strain -- at any rpm. Try changing your X dimention to get more rpms. Your target is 5800 with an average load. <br /><br />Yes, any prop will flex. And yes it will lose some bite over time.<br /><br />Good luck!

 

[StriperChaser]

Re: Alum Prop Flex

Dhadley,<br />What manual are you using? The one that came with that motor and the repair manual both say 4800 to 5200 RPM at WOT is normal operating range. Where are you getting 5800? Please explain how to change the "X dimention". Is that a change in prop pitch and / or size? I would like to get the RPM's up a bit. <br /><br />I did a search on "X dimention" and see it has to do with raising the engine, I think. I carry 40 gals of fuel, and 3 heavy duty batteries in the stern. A 30 gal live well and another battery just in front of the console plus passengers and gear. So you see I'm pretty loaded. Would raising that motor a notch help or hurt? Any other recommendation other than to lighten the load?