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Volvo penta stainless duo prop balancing

Fishmaster23

Regular Contributor
Can these props be balanced? I had a new hub put on thinking that was the issue. I asked the prop shop about re pitching and he said he can't switch those big elephant ear style proper because they will just crack. Somehow I got off topic and didn't ask him about balancing them. They're the old Volvo stainless dpa props. It says 2170 on the rear prop, not sure what number that translates to C5 or C6 Maybe?
 
These props are on an entirely different outdrive and I still get the same vibration. It's not really a shake the boat vibration, but more of a buzz your feet kind of vibration when standing up on deck. Just like something is slightly off balance. Isn't noticeable until above 2500rpm.
 
There have been discussions regarding the propellers needing to be phased correctly.

Remove the AFT propeller.
Bring the forward propeller around until one blade is at the 12:00 O’clock position.
Without disturbing the position of the forward prop, re-install the AFT propeller so that one blade is at the 6:00 O’clock position.

Give it a try.


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I'm pretty sure they are. It's the center of the propeller that's out of whack. Of you look at the space between the nose cone and the propeller it increases and decreases. It did the same thing on the other outdrive.
 
Well the end of each blade is at 12 and 6 but I wonder if the edge of each blade needs to be straight up and down and not the entire blade itself.
 
The timing has more to do with efficiency vs creating vibrations. Looks like these props have been balanced before at one point, you can see where they've grinded on them.
 
You should take these questions to a good propeller shop and ignore the opinions of the people on this forum.
 
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Can these props be balanced? I had a new hub put on thinking that was the issue. I asked the prop shop about re pitching and he said he can't switch those big elephant ear style propeller because they will just crack. Somehow I got off topic and didn't ask him about balancing them. They're the old Volvo stainless dpa props. It says 2170 on the rear prop, not sure what number that translates to C5 or C6 Maybe?
I think what you are describing as the "elephant ear" prop would be your FWD prop, not the rear (AFT) prop...... Yes/No?

These props are on an entirely different outdrive and I still get the same vibration. It's not really a shake the boat vibration, but more of a buzz your feet kind of vibration when standing up on deck. Just like something is slightly off balance. Isn't noticeable until above 2500 rpm.

I'm pretty sure they are. It's the center of the propeller that's out of whack. Of you look at the space between the nose cone and the propeller it increases and decreases. It did the same thing on the other outdrive.
OK, since you now mentioned "nose cone" (i.e., the AFT prop nut or spinner), you would be talking about the AFT prop........ Yes/No?

The timing has more to do with efficiency vs creating vibrations.
I believe that is correct.

True, but no reason to ignore advice given here.
With exception to the uncalled for comment in post #8.

I checked them, they look like they're clocked correctly, so it has to be the props themselves.
Since you've tried this set on a different DP drive (assuming that both prop shafts are true) and feel the same results, I would agree.



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That's correct. The shop said he can't re pitch my style of prop because the surface area is too large and they will just crack. So I guess we thought the hub itself was causing the vibration. He said it was typically caused by missing spacers, which was also true it my case, but I wonder if the prop being out of balance can destroy the hub.
 
That's correct. The shop said he can't re pitch my style of prop because the surface area is too large and they will just crack. So I guess we thought the hub itself was causing the vibration.
1..... He said it was typically caused by missing spacers, which was also true it my case,
2..... but I wonder if the prop being out of balance can destroy the hub.


1..... if the FWD propeller spacer ring is NOT installed, the FWD prop will damage the prop shaft bearing carrier, and eventually ruin the AFT most seal.
If that has not occurred, you have one of two things going on:

.... the spacer was NOT omitted.
.... you are extremely lucky.


2... The A and B series DP's have an inner hub. That hub is trued and is then inserted into the propeller hub with an epoxy bonding product. I do not know if out-of-balance-vibration could cause damage to this bond!

The C series is built a bit differently.

Neither of these offer thru hub exhaust. That would be with the next generation DP.


AQ series Duo Prop propellers.jpg

 
The aft propeller thrust washer was the one missing. I bought a new one at the fine tune of about $65. Actually I even tracked down the two oem line cutters both of which had the thrust washers integrated in, so I have two extra thrust washers.
 
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The aft propeller thrust washer was the one missing.
Have you examined the AFT-most end of the prop shaft bearing carrier?

I bought a new one at the fine tune of about $65.
Yep.... they are very proud of those!

Actually I even tracked down the two oem line cutters both of which had the thrust washers integrated in, so I have two extra thrust washers.

NOTES:
The spacers/thrust washers that fit into the line cutters are slightly smaller than the ones that do not.
Make sure that the line cutter can be pressed into the recessed area of the prop hub.

The line cutters are more effective if you cut a few small slits into the outermost edge, allowing them to actually "cut" any fish line.
 
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