Unbalanced prop - how to tell

[Joseph10]

Hello,
I just got my propeller back from being repaired for the used tracker boat I just bought (2005 tracker with Merc 50ELPTO).

I noticed a "different", louder, engine noise at a certain RPM (~4200). How can you tell if a propeller is unbalanced?

My concern is that the repair shop did not balance it correctly, and that may be what is causing the odd behavior at that certain RPM range.

Is there a tell-tale sign for an unbalanced prop?

Thanks,
Joseph

 

[5150abf]

Re: Unbalanced prop - how to tell

I don't know that it would cause a noise but certainly vibration.

If your boat were shaking or vibrating more at a certain speed I would look at that.

 

[Joseph10]

Re: Unbalanced prop - how to tell

Thanks. Would symptoms of an unbalanced prop only show up at certain RPM ranges?

 

[steelespike]

Re: Unbalanced prop - how to tell

It may not be a balance problem.could be poorly tuned.But what ever it would be noticed at certan specific rpms,whether balance or tuning.
Can you tell if is simply a different motor sound or a vibration?
If the prop was chewed up a properly tuned prop would surely sound different.If you suspect the prop perhaps the prop shop would check it for balance and pitch.The dinged prop could have been masking normal engine sounds or making the sounds appear at different rpms.

 

[Joseph10]

Re: Unbalanced prop - how to tell

Hello. It is just a different engine sound (like it gets louder or is lugging). I don't notice any vibration. It only happens at 4200-4300 RPM. It sounds normal at all other RPM ranges.

The reason I thought it might be the prop is because I just had it repaired prior to taking the boat out for the 1st time. However, I just bought the boat and do not know what it sounded like pre-repair.

 

[steelespike]

Re: Unbalanced prop - how to tell

Sounds to me like just a normal progression of the sound.Does the motor reach its rated max rpm?

 

[Joseph10]

Re: Unbalanced prop - how to tell

The "loudness" goes away after ~4400 RPM and the motor reaches ~5300 RPM with the boat @ 32 MPH (max rated RPM is 5500). On the new tracker PT175 they list 30-31 MPH for this boat/motor, so that seems about right.

Thanks,
Joseph