Hit the clay, prop slightly bent, weired RPM now...

[rokrau]

Solas Amitas 4-blade - 14x21 Aluminum (bought last year here)
Volvo Penta 4.3GL w/ Penta-SX
Larson 180 SEI, 2 adults - 3kids - 1dog - 1/4 tank of gas

Ok, took the boat out yesterday and we very slowly motored into some real shallow area where we hit the clay. Stopped immediately and raised the outdrive and there was actually clay on the prop. But the prop was also bent ( a quarter sized area on one of the blades, abrasion on the others ).

Then the tach was off by about 500 on slow forward >1000 rpm on 80% WOT, (i.e. it showed > 5500 RPM) but the engine actually sounded exactly as it did before. I also didn't notice any difference in hole shot or overall performance either. Except maybe a bit rougher sound when steering towards starboard but I was also getting slightly paranoid by that time.

We cruised around some more and at some point when I was running almost WOT the tach jumped back and RPM showed normal range ( 4200-4500 RPM ) but later when getting to the dock it was again 500RPM more than expected (show 1500RPM when slowly approaching the dock).

Is this a spun hub? If it is - what do I do next? If it's not what do I do to diagnose the problem? Where does the tach get it's signal?

Thanks for all help !

 

[Bondo]

Re: Hit the clay, prop slightly bent, weired RPM now...

Ayuh,... Change the Prop,+ check the Grounds to the dash....

 

[JaseBosto]

Re: Hit the clay, prop slightly bent, weired RPM now...

While the drive is in forward, grab the prop with both hands. Try to turn it. You may have to man-up for this, because even if the prop hub is spun, it will take some grunt to spin it on the hub. My next step after that, if its not spun, would be to take the prop off and have it repaired because being bent or otherwise f'd up isn't how its supposed to be.

 

[rokrau]

Re: Hit the clay, prop slightly bent, weired RPM now...

Ayuh,... Change the Prop,+ check the Grounds to the dash....

Oh, an electrical problem.... :redface: That could well be.
Thanks for the hint.

 

[rokrau]

Re: Hit the clay, prop slightly bent, weired RPM now...

While the drive is in forward, grab the prop with both hands. Try to turn it. You may have to man-up for this, because even if the prop hub is spun, it will take some grunt to spin it on the hub. My next step after that, if its not spun, would be to take the prop off and have it repaired because being bent or otherwise f'd up isn't how its supposed to be.

Thanks for the tip, will try today. I guess it's a trip to the prop shop then. I've read that I can mark the props location and run it and then check again for slip. I guess if the hub is spun there is no point fixing it at all right? The one I have does not have a hub kit...
Would a prop shop be able to tell whether the hub is spun?