See full version: Sterndrive Show-Down: Volvo-Penta Duoprop vs. MerCruiser Bravo III
Just a few short years after Volvo-Penta introduced the Aquamatic sterndrive, its competitor Mercury Marine quickly followed suit and introduced stern drives of their own. The next great leap forward in sterndrive technology came in 1982 and was again pioneered by Volvo-Penta, when they introduced the twin-prop Duoprop drive. Mercury’s answer? The MerCruiser Bravo III.
The Volvo Penta Duoprop comes in DPH, DPS, and DPR versions, which are available to match different gasoline and diesel power systems up to 380-hp. Volvo claims a few unique features, including a patented hydraulic and X-act steering system with direct-mounted external steering cylinders, and the Powertrim Assistant on EVC (electronic vessel control) models, which trims the drive automatically to predetermined setpoints. here
So: if you’re buying a new boat, which system should you choose? It's impossible to objectively say which is "best" because there are so many variables involved, some of which may be more or less important to one person or another. Naturally, you’ll also want to consider the ins and outs of the stern drive powerplants built by these two companies. But a lot will depend on what brand of boat you buy, as well. If it’s built by Brunswick, the nation’s largest boatbuilder, Volvo-Penta won’t even be an option—Brunswick also owns MerCruiser, so naturally, that’s what they put in their boats. Another factor to consider is the dealership you’ll be buying from, and your relationship with them. No matter how well your boat runs it’ll need to be serviced and maintained, and a close-by dealer who’s reliable and fairly priced can make boat ownership a far more pleasant experience.
Re: Selecting props for volvo penta DP here
I do have two SX props available - both alum. One is a 19 pitch 3 blade, other is 20 pitch 4 blade.
Re: Selecting props for volvo penta DP
A set of F2's just listed on ebay in Florida under Volvo Duo Prop in the boat acc section. here
F2 absolutely if you are going to be in Denver area lakes.
Outdrives rebuilt by Certified Mechanics
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Call 913-342-0011 for assistance. Please have your engine serial number available if possible.
here
Remanufactured
1 Year Warranty here
US Boatworks- Quality Sterndrive Remanufacturing for over 35 years. [links]
No need for a Torx T60 a 1/2" AF Allen key will do. (however the whole job can be done with the pivot housing in place, but much easier with it removed) [links]
If you have a water leak into the bilge from around the drive-shaft opening, then you are correct in your assumption that the u-joint bellows is leaking and water is getting back into the boat. You don't want to waste too much time fixing this. The u-joints are getting wet quite a bit which will lead to their premature failure. Same goes for the gimbal bearing. Also, if the yoke (where the driveshaft enters the drive) rusts it has a tendency to tear up the shaft seal which will let water into the drive as well.
If the 2 "O" rings on the shaft are in reasonable condition then you are OK to re-use them. But the fact that water was leaking into the boat means that water has passed through the Gimbal bearing and also passed the seal that is forward of the bearing so even if it was fresh water they will need replacing.
Hey there-searched through the stickies and only found the SX bellows replacement so I started a new thread. I have a 2005 DP-SM 1.78 (M22) with SN 3868912 or 4202142350 drive and a water leak. Originally I thought it was the steering pivot seal leaking and replaced it and still have water. After hanging upside down in the bilge on the water yesterday, I saw that I have water dripping off of the driveshaft and onto the exhaust y-pipe and into the bilge. I'd like to assume it's the drive bellows at this point. First, is there another spot where the water could be leaking? It's not around the inner transom assembly and it's not the pivot seal for the steering. I know the raw water enters there as well and I just can't get to a vantage point to confirm where the water is coming in.
The difference between the DP-S drives and the SX drives is the lower gear housing. The upper housing is identical so the SX bellows replacement thread you found will help you nicely in your work.
Your correct about the non serviceable U-Joints. At some point in 2000 Volvo Penta changed the U-Joint assembly to a factory balanced design that was not meant to have the spiders replaced on. I have a 1999 DP-SM with the older Rocket U-Joint assembly, you have the the newer, balanced, GKN U-Joint. more
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Gas Engines: AQ175, AQ205, AQ430, AQ431, AQ432, AQ434, AQ200, AQ225, AQ260, AQ211, AQ231, AQ271, AQ500, AQ570, AQ572.
Diesel Engines: AQD40A, AQD40B, AQAD40A, AQAD40B, AQAD31, AQD41, AQAD41.