The good news is, you can use either hand propeller on this drive.
The reason is that Volvo Penta's lower unit hypoid gear cut is designed to NOT have what would otherwise be a "drive" side or "coast" side to the gear cut. They are designed to carry the full load in either rotation direction.
The upper transmissioin gears and cone clutch don't care one way or the other.
As said, to change prop hands, it requires a simple change to the vertical shift rod just inside of the rear shift mechanism cover.
You may want to re-adjust everything to absolute neutral, but that too is fairly easy.
Here's the other part to this.
When running a LH prop, we're driving from the transmission's lower "driven" gear.
When driving from the lower driven gear, this places an up-lift on the transmision vertical shaft.
(this has to do with the steep spiral cut splines for the brass sliding sleeve)
There is a brass split ring keeper at the lower area of this shaft that "checks" this up-lift.
These brass keepers become expanded from the split ring, and will eventually let go.
Here is a transmission vertical shaft.
The keeper is the brass ring with the green arrow pointing to it.
(Volvo Penta calls this a wear washer)
(later drives went to a larger diameter vertical shaft and a stress proof steel keeper, and they have no issues with them)
If you have been running a LH prop for years and years, I can just about guarantee you that the OEM brass keeper is due for replacement.
You DO NOT want this part to fail..... trust me on this!
Conversely, when running a RH propeller, this shaft has a downward force applied to it, and the top nut takes the downward force load.
This does not let us off the hook for replacing it, however, because reversing still puts force against this part.
FYI.... I have and sell custom manufactured stress proof steel keepers, if interested.
(Volvo Penta does not offer these for this series drive)
The other thing is the trim fin/torque tab.
With the 280, 290 and SP drives, the trim fin/torque tab seems to work just as welll with a LH prop as it does with a RH prop.
This is not true of the 250/270/275 style trim fins.
These fins offset prop torque best with a LH propeller.
I hope that this helps you.
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