Converting AQ280PT to Duoprop

[Schonl]

I purchased a DP lower unit and attempted to install it, or I did install it... I went to the lake so excited to test it out and when I put it in gear nothing happened, yep should have tested it first. After reading on Iboats and measuring the shafts I realized I needed a longer shaft coupler which I am waiting on from eBay. I used the original Race and shims that came with the lower unit. Instead of doing the shim math I just measured the depth of the hole the race goes in and depth was the same as the intermediate unit that the dp lower unit was originally attached to. Shouldn't that be correct? When I had the lower unit installed I also noticed it was harder to turn than the original lower unit, is that a common characteristic of the DP? Just want to be sure I'm on the right track. Any help or comments would be greatly appreciated. Thanks

 

[zool]

You absolutely need to reuse the roller bearing race from the dp like u did or buy new, but you also must follow the shim procedure as defined in the manual. You use a negative preload, not positive. You take like 10 measurements and use the most common. Some of the later dp-c drives had a shorter verticle shaft, so a longer spline coupler is required.

I believe you also need to convert from engine oil to GL-5 gear oil.......proper shimming and the right ratio for ur engine is very important on the aq drives.

 

[zool]

here the manual if u dont have it
http://www.marinesurveyorontario.com/volvo penta workshop manual.pdf

 

[Scott Danforth]

what vintage lower did you get?

as far as turning the drive, are you referring to steering or spinning the props? steering should not matter. as for spinning the props, you have twice as many things turning in a DP lower