Calling Don S.Volvo Penta DuoProp 290-Props not Turning

First time poster here at Iboats. Spent the last few hours reading all kinds of great info. Don S. I hope you're still around because you appear to be the outdrive guru.

Here's my siuation. Twin 1989 AQ 271Cs / DuoProps 290 A? B/ Not sure.

Props aren't turning when I drop in on forward or reverse with engine running. Cable appears to be moving shift mechanism normally. (I have twin drives so I'm comparing the non-working unit to the good one.) With the rear cover off I manually rotate the shift mechanism and the props will only turn one direction depending on whether in forward/reverse. So I'm only guessing that it has something to do with the upper unit.

What I'm hoping for is a list of possible suspects, perhaps a typical problem with these drives. I'm a live aboard so once I have the boat pulled, the clock will be ticking since I'll be staying in a hotel & paying boatyard fees each and every day. $$$

Any suggestions on the logical order of things to check to identify the problem would be appreciated.
Thanks, Glen

Re: Calling Don S.Volvo Penta DuoProp 290-Props not Turning

Remove the upper gear box and see if the coupler that connects the upper and lower vertical shafts is broken.

Re: Calling Don S.Volvo Penta DuoProp 290-Props not Turning

Thanks for the fast response.

I will do that. I don't have the manual in front of me... Once I remove the upper housing, how will I know the if that's the problem? Will the gear etc just lift out?

Also. if and when that piece fails, does that lead to metal fragments throughout the drive?

Gratefully Yours,
Glen