Thread subject: Whaler Central - Boston Whaler Boat Information and Photos :: Vibration from wrong or damaged prop?
Posted by ecjacobson on 09/16/23 - 12:22 PM
#1
Whole boat vibrates at low speeds. Fine at idle or up on plane. Is this because of the ding on my prop or could it be bad prop size?
2017 Montauk 170 with Mercury 90hp. Propeller is Vengeance 13.125 X 16. I bought it from original owner July 2022 and didn't notice the prop ding or any vibration last year. But I may have just overlooked both or either in my excitement. Noticed the vibration all summer this year, though. So I figured I would replace the prop when I winterize.
Big dilemma is whether or not to replace with same prop model and size, or try something different. I'm rather overwhelmed by prop discussions but it seems lots of people use 19 pitch for that boat/motor.
Also I'm quite confused as to whether my motor has command thrust. I think gearing is 2.33 rather than 2.08. Original invoice says L4NA 4 cyl. Model# is 1F904131D. Manufactured 2016.
Would love to maybe try a better prop in case the vibration was prop size/type. Any suggestions? We use boat for general use on freshwater inland lake. Mostly skiing, tubing, tooling around, some fishing.
Included pic of prop damage. I have no idea if that amount of prop damage is likely to cause vibration.
Posted by ecjacobson on 09/16/23 - 12:23 PM
#2
a pic of other side of prop, showing scratches.
Posted by Phil T on 09/17/23 - 7:47 AM
#3
Could be harmonic resonance.
Could be the hub.
Could just need the prop blades to be cleaned up.
Take a video of the boat running with the vibration.
At what RPM does it start.
At what RPM does it stop.
Does it resonate in advanced neutral?
Are the rails vibrating?
Posted by ecjacobson on 09/18/23 - 4:43 PM
#4
Right, I need to answer some of those questions. I'll post back when I can. Thanks PhilT.
Posted by ecjacobson on 09/22/23 - 4:25 PM
#5
Could be the hub. - yep. I'll replace it.
Could just need the prop blades to be cleaned up - planning to get the repaired at a local shop
Take a video of the boat running with the vibration. - there is no way it would show in the video
At what RPM does it start. - 2100
At what RPM does it stop. - 3000 maybe, but at that point the boat is starting to plan and the vibration is not really noticable
Does it resonate in advanced neutral? - I forgot to check
Are the rails vibrating? - no, I guess not
I think I'm all set. No need to respond.