Squealing Noise from Prop

[Pony]

G'day all;
First post and straight away I'm asking for advice.
I have a 15 HP 4 Stroke Honda on a 3.7m Barra Punt, I have just bought a new Prop from Solas, 91/4 x 7P. The old Prop is 91/2 x 85/8P, I dropped the pitch because when I carry 2 people and a bit of weight, she struggles to plane.
Anyway, I put the new prop on and just above idle there is a sort of squealing noise, when the motor is revved a bit more the noise goes away and prop works good.
I took the new prop off and looked for any wear marks as I thought that the new prop was rubbing on the motor, I couldn't find any rub marks.
Put the new prop back on and same thing put the old prop back on, no noise of any sort, put the new prop back on and noise is once there once again.
I have called Solas and they have told me to send the prop back, which I will do next week.
Just wanted to run it past you guys, in case I am missing something real simple.
Thanks
Pony

[NQCairns]

No idea what is going on but I suspect it is real simple as you say, look forward to hearing what transpires. A long shot could be the bush is slipping causing the squeal then heating up and grabbing as if there is no slip that you can notice anyway.

[basserman]

when you have been doing this has it been on a set of muffs or in the water???
if it is in the water then something like NQ said might be the cause as there is a bit of pressure on the prop however if it is on the muffs i would think it might be rubbing somewhere

[Pony]

Thanks for the reply's fella's;
All the testing was done in the water, I haven't had a chance to look at it again, but I will go out now and put the muffs on and see if I can find out a bit more.
I never thought of a slipping bush, I just assumed that if the old prop worked fine, straight after the new one didn't then the motor should be OK.
Will keep you all updated.
Pony

[Pony]

OK update time.

I went and changed the gearbox oil, crankcase oil (4 stroke), greased every pivot point, tightened the steering friction bolt and tightened or greased every other thing that could possible vibrate or rattle, checked the thrust washer was on.

Put the muffs on and startered her up, put her in gear, no noise. I tried and tried to get it to happen but it was gone. You beauty, so I thought I would take a quick run up to Tinaroo Dam, just to make sure it was gone.

Got to the Dam, put her in the water and just off idle that bloody noise is still there. Tried trimming the motor up and down in case there was a bit of wear or something, no good. Tried trimming right up to the shallow running position, no good.

So I'm stuffed if I know, it is a squealing noise that is at a certain revs just off idle. If I keep the revs constant the squealing stays constant, if I rev it up or take it back to idle the noise goes away. There are no rub or wear marks on the prop or motor, and put the old prop back on and there is no noise.

So unless anyone has got any idea's I'm going to send the prop back to Solas in the next couple of days.

Pony

[blaze]

its a strange one
just above idle = no torque applied, no blade flex, bushes dont normally slip at idle (ive had them slip under power but also been able to get home well above idle and know noise)
any movement in the prop shaft?
cheers
blaze

[NQCairns]

Possible vacume leak then? considering it is around idle? Just wild guesses, why did they want the prop back after you told them the symptoms? confusing, could the noise of the engine be overpowering the noise from just above idle and beyond?

[blaze]

nq
airnt 4 stroke supposed to be quiet, certainly a strange one.
where does the exhaust come out, not a deformity in the prop creating a noise (like a small hole creating a whistle)
yeh I know, let go of it but wee are drawing at straws ah
cheers
blaze
ps
thought if I put that ah in there i may sound like a queenslander

[Davo53]

Hi. I have had something similar happen with a solas prop on a Honda 75. It made a funny sqealing/ringing noise at low revs. turned out it was cavitating, ie bubbles forming on the prop. This will eventually blister the paint off in spots. Solas were no help at all, claimed I must have damaged the prop, which is crap because it happened from brand new.
Check to see if the paint is coming off, ( assuming it is painted black?) As I recall this took a while to happen.

Good luck.

[Pony]

Alright;
Update time, Solas have replaced the prop, no worries at all. Got the new one this arvo, went straight out to the Dam and this one squeals louder than the last one.
But exactly the same noise at exactly the same revs. WTF
I'm really at a loss here, put the old prop back on and no sign of the noise, new prop and back it comes.
But new prop in reverse or with the muffs on and out of the water and no noise.
Its got to have something to do with the the prop "biting" through the water but I'm buggered if I know.
Davo, I will keep an eye on that.
But at the moment I'm thinking off just ignoring the noise. Anyone see any problems with that?
Thanks for all your input guys.
Pony

[FNQCairns]

Hi Pony, crap like what you are dealing with shouldn't happen! if it were me I would look toward a getting my money back and try a prop from a different manufacturer.

Solas would know what is going on with their prop design and if they wont come up with the info and just leave you hanging like your time is cheap or worthless it's time to kick them of the gunnel.

I suspect as mentioned that it is cavitiation that will harm your investment over time.

Honestly on the prop tree the aftermarket Aussi ones are hanging close to the ground, consider what diameter and pitch you think you need and check out some of the props in the US.
Props ain't Props sol. Sorry if you are too young to remember that saying. Good luck with it. cheers FNQ