Duro prop not engaging

[hbbutler]

Having problems with the gear engaging late . It is a recent development could something be out of adjustment? Thanks in advance.

 

[RicardoMarine]

You do not mention which Duo Prop drive.


It may be an adjustment, and that would be the place to begin.
Start by disconnecting the vertical linkage arm at the eccentric piston.
Put the eccentric piston in the neutral position.
If AQ series, adjust all else to this, making sure that the "gear yoke" does not come down into contact with the Intermediate housing during a full shift into FWD.
(shift cable must always extend at the drive for FWD engagement)
This is slightly different for some DP-S style drives.

Once initially adjusted, remove the barrel fitting from the gear yoke.
Do a full FWD and REV shift lever travel.
Check for cable "over-travel" in both directions..... you will have some.
Adjust as to "split" this over-travel.
Check neutral once again.
All linkage components should easily drop back into place while in neutral.


Other possibilities:
Bronze material from a bronze sliding sleeve has become bonded to the gear cup(s).
Incorrect gear oil.
Water contaminated gear oil.
Synthetic gear oil used in an older transmission.
Any contamination between the sliding sleeve and gear cups.


No where in the OEM service manuals will Volvo Penta discuss lapping a bronze sliding sleeve and cups.
This does work, and I have great success in doing this, but there are some precautions that I'd suggest.
Basically, you're on your own if you attempt this. It will work when done correctly.

NOTE: the steel sliding sleeves and coated gear cups cannot be lapped.

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