Propshaft play ?

[L.Tomahawk]

Well after 8 years of not at much as hitting a piece of sand it finally happened, hit a rock ....... Did some damage to the prop ( not real bad ) put a rebuild prop on, put back in water. At low speed heard what sounded like cavitation or a high pitched noise, then at 4000 rpm the service engine req. came on ???

Took the boat out, looked at prop, nothing out of the ordinary. Did some checking on the forums, shaft looks fine, strut looks fine, bushings keep the shaft centered ( though there is a very very small amount of play )

When I spin the prop by hand there is a small amount of play before the shaft engages the gear ( I feel the prop is sitting on the shaft and key properly )

I never had to replace the prop before or ever felt around under the boat when it was new to get a feel for how things should feel under her...... Never turned the prop by hand to see how it was supposed to feel ......

Any help would be greatly appreciated?

Also no vibration at any speed ......

Edited August 7, 2015 by L.Tomahawk

[GreenMan]

If the prop is firm on the shaft (are you sure the prop is not 'rocking' on the shaft?), go looking at the other end of the shaft. Might need someone to rock the prop back and forth while another looks around at the back of the transmission.

You're looking to see:

1. If the shaft is loose inside the drive coupling hub - probably means the drive key is damaged.
2. If the coupling hub is rattling around loose behind the transmission drive flange - check the four bolts in the coupling hub are in place and tight.

[tvano]

Well after 8 years of not at much as hitting a piece of sand it finally happened, hit a rock ....... Did some damage to the prop ( not real bad ) put a rebuild prop on, put back in water. At low speed heard what sounded like cavitation or a high pitched noise, then at 4000 rpm the service engine req. came on ???

Took the boat out, looked at prop, nothing out of the ordinary. Did some checking on the forums, shaft looks fine, strut looks fine, bushings keep the shaft centered ( though there is a very very small amount of play )

When I spin the prop by hand there is a small amount of play before the shaft engages the gear ( I feel the prop is sitting on the shaft and key properly )

I never had to replace the prop before or ever felt around under the boat when it was new to get a feel for how things should feel under her...... Never turned the prop by hand to see how it was supposed to feel ......

Any help would be greatly appreciated?

Also no vibration at any speed ......

high pitched singing? search for prop sing

[L.Tomahawk]

Ok, so the noise issue is resolved??? But can the singing rob power ?

How about the shaft play ?

Will look into your idea GreenMan ......

davemac, on Jul 11 2008, 01:03 PM, said:

Update: PROBLEM SOLVED... it was "prop singing". I put a new acme 515 on and noise is gone. I will keep old prop as spare, and recondition at year's end. Again, the "whistling sound" only occured in Forward gear from idle up to 1,000rpm.

If anyone is interested, here is the response to my inquiry to Acme marine...

"Your description of what we call a singing propeller is correct, including the rpm that is happens at. If you take a file & square off the trailing edge of the propeller the singing will go away. You will find a flat spot on the trailing edge of the cup that is the part that needs to be squared off."

Dave

I'm having the same noise since I put on a brand new prop, could a new prop need filed? If so, can you clearify the location I need to file, close to the hub? entire trailing edge?

Edited August 7, 2015 by L.Tomahawk