Volvo Penta 280PT single prop to 290DP suspension fork swap HELP

First my apologies for the long first post. i just want get get it all out there to get the best help possible.

good day all, new to the forum, but I've been reading for a long time, this is a great forum, it has helped me with power steering issues, sea water pump selection, and i even changed my PDS bearings and U-Joints just by reading previous post. thanks for that.
to the question, my boat has a gm 5.7L branded as a Volvo penta and it has a 280PT single prop outdrive. now last trip out was 22 miles off the coast of Galveston TX. and back at the boat launch i heard a noise, back at home doing the salt water wash down, i put it in drive and now i hear noise from the upper gear box and the lower as well and the prop is squealing, i removed and no lines have been tangle inside, after some inspections i determined there is water in the outdrive, i believe its shot. so time to upgrade, I've read that the 290DP is a much better option. and I've read that the 280 and the 290's have the same intermediate housing, so i want to swap the 280 for a 290DP according to reading some previous post i can just change the suspension fork from the 280 to the 290 and we can bolt it back up, my current 280 has a 1.61 ratio and again from reading i need a 1.95 ratio for the duo prop. that all sound pretty easy, but after reading some of ricardomarine post on the shimming and pre load or negative something i am terrified of an attempt to do this my self. i am pretty mechanically inclined but this procedure i'm not sure. so the real question is if i remove the lower 290dp leg to replace the suspension fork, do i have to re shim any thing or all the other stuff that Ricardo is very adamant about doing when these uppers and lower unit are separated. i do understand that as it is open to go ahead and replace the o rings and seals. i have a lead on a 290DP C with the props for $400. your help will be greatly, thank you in advance.

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ramon gonzalez said:

..............., my boat has a gm 5.7L branded as a Volvo penta

.......I've read that the 290DP is a much better option.
Better, but not as good as it could be.

and I've read that the 280 and the 290's have the same intermediate housing,
Correct!


so i want to swap the 280 for a 290DP according to reading some previous post i can just change the suspension fork from the 280 to the 290 and we can bolt it back up,
That is doable.

my current 280 has a 1.61 ratio and again from reading i need a 1.95 ratio for the duo prop.
For the SBC, that is correct!

that all sound pretty easy, but after reading some of ricardomarine post on the shimming and pre load or negative something i am terrified of an attempt to do this my self.
There is no need to re-shim anything if you are simply changing the suspension fork.

so the real question is if i remove the lower 290dp leg to replace the suspension fork, do i have to re shim any thing or all the other stuff that Ricardo is very adamant about doing when these uppers and lower unit are separated.
Again, if you are simply changing suspension forks, and going back together with the same transmission, Intermediate housing and lower gear unit..... no!

i do understand that as it is open to go ahead and replace the o rings and seals.
Absolutely!

i have a lead on a 290DP C with the props for $400.
There is no such thing as a 290DP-C.
The DP-C is a later style AQ series Duo Prop drive, and with a much better hydraulic trim system.
The DP-C, and all of it's components, is what I would recommend going with.

Now, if that the C follows the serial number, then that would indicate that the 290 is for a 4 or 6 cylinder engine, in which case it would be the 2.30:1 reduction.
You cannot use the 2.30:1 reduction.

For only $400, I'll bet that's what it is.

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Ricardo thank you for the reply,
I am going this afternoon to inspect the 290,
If all goes well I will be installing soon.
What would be the torque specs for reinstalling the lower back to the intermediate section or where can I find the torque specs.

ramon gonzalez said:

Ricardo thank you for the reply,
I am going this afternoon to inspect the 290,
If all goes well I will be installing soon.
What would be the torque specs for reinstalling the lower back to the intermediate section or where can I find the torque specs.

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Make sure that it's the 1.95:1 reduction. The numbers will be stamped into the prop shaft bearing carrier.

As for the torque values, it's always best if the owner looks up his own specs in his OEM manual.
This avoids any chance of misinterpretation, etc.


.

after looking at the out drive it turns out to b a 2.3 ratio. that is stamped on the prop shaft carrier and the tag also says 2.3 there is no C in the serial number, it has in the model DP-C2, i could not snap any photos as my phone was very low on battery,
whats odd id the were attached to a 30' cruiser that had twin ford 5.0 v8 302 fuel injected branded as Volvo penta. the only thing the seller knew is it was re-powered in 1998 all indications is that it had from factory twin v6.
now could it be possible when they re-powered it they also upgraded the out drives and forgot to re-stamp the new ratio? it looks like a very clean out drive the only thing is 1 broken bolt on the hat bushing overall it looks good.
what would the procedure be to check the actual gear ratio?
i have another lead on another 290dp that i will look at this evening.
thanks for your help.

here are some pics of a 290 dp with stainless props that is attached to 5.7L v8. hopefully this one will be a 1.95 ratio, the engine threw a rod and has not move in over a year, what worries me is the gear selector will not move from neutral to forward or reverse, even after i remove the cable. its very hard and i really didn't want to force much so is this normal for a unit that has been sitting this long? or should i walk away. i have not been around these much to know i saw 2 others today as well that came off a bayliner with twin 290 dp unfortunately they were 4.3 v6 with a 2.3 ratio on of them was very stiff in the gear selector and the other move but also stiff, on mine i could switch from neutral to forward to reverse very easily when i had it off the boat when i replaced the pds bearings. it is on a v8 and the seller is going to remove the props to verify the gear ratio on the ring itself since the tag is missing. your help would be greatly appreciated

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ramon gonzalez said:

here are some pics of a 290 dp with stainless props that is attached to 5.7L v8.
That is NOT a 290 DP, at least not in it's entirety.
The drive that you show has the cylinders attaching directly to the suspension fork.
The 290 and SP use a SS Anchorage Bracket that the cylinders attach to, and it still maintains a version of the reverse latch system.

hopefully this one will be a 1.95 ratio, the engine threw a rod and has not move in over a year, what worries me is the gear selector will not move from neutral to forward or reverse, even after i remove the cable. its very hard and i really didn't want to force much so is this normal for a unit that has been sitting this long?
Drain the gear oil, and remove the four bolts that secure the shift mechanism to the transmission housing.
Pull it off and look inside.

or should i walk away. i have not been around these much to know i saw 2 others today as well that came off a bayliner with twin 290 dp unfortunately they were 4.3 v6 with a 2.3 ratio on of them was very stiff in the gear selector and the other move but also stiff, on mine i could switch from neutral to forward to reverse very easily when i had it off the boat when i replaced the pds bearings. it is on a v8 and the seller is going to remove the props to verify the gear ratio on the ring itself since the tag is missing. your help would be greatly appreciated
NOTE: if a gear set has been replaced with a different reduction set, and if the mechanic did not re-stamp the carrier, the ratio may be incorrect for your use.






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Ricardo, thank you for the info, i have moved on from that unit and still in the hunt. my local Volvo penta dealer wants 21 hours of labor plus parts to repair mine, so that is out of the question. i have found several good units at a decent price but the gear ratio is either not a 1.95 or questionable as its not marked. thanks for all your help.