Mercruiser vs Volvo Sterndrive Systems

[joliette]

I'm looking for used / reconditioned twin engines (V6s) and drives for my Settimo Velo project (http://www.facebook.com/#!/group.php?gid=179427293999).

I am wondering what way to go - Mercruiser or Volvo?

What are the pros and cons of each?

I'm leaning towards Volvo because I like the DP sterndrive and the ability to set standard Volvo drives on opposite rotation (not possible with standard Mercruiser drives). Beyond that, are there any differences in reliability and maintenance costs?

 

[spannerman]

You can run Bravo I & II drives either way (only Alpha drives are handed), we have Hydrolifts with twin Yanmar diesels and twin Mercruiser 350hp engines running Bravo I's in both directions. Or you could just go for the Bravo III which is then same as a Duo prop.
Having repaired over 200 VP drives and barely a handful of Mercruiser drives in the same past 16 yrs I'd go for Mercruiser as they almost never get water in them due to the positive pressure oil reservoir on them.
If its a performance boat then its worth fitting a drive shower to help cool them.
VP leak like a sieve, you only need a bit of fishing line or sea grass round the shaft and the seals are shot, if you catch it in time its easy enough to replace the seals and flush them out, but if you don't catch it the lower gear on the vertical shaft loses its teeth and then the lower section is scrap, its not worth rebuilding as the hours involved in changing bearings and gears and shimming it all to the correct clearance isn't viable, so we always replace the lower section plus it has a guarantee.

 

[lovezoo]

I'm glad that one of the acknowledged forum experts with real live hands-on experience has confirmed that there is in fact a difference between Volvo and Mercruiser outdrives. Maybe explains why some people on here believe that outdrives are the work of the devil and will destroy your very soul and/or sink your boat/wallet/marriage and will almost certainly cause your dog to explode.

Others on here (such as myself with a nice shiny Alpha 1 Gen II outdrive) haven't found maintenance too hard or expensive to do over the past 5 years of ownership (and my dog hasn't gone pop).

Spannerman: can you also confirm that Mercruiser bellows are made of thicker plastic than the Volvo equivalent?

 

[rubberduck]

Mmmmm, I did wonder why my new Volvo boat had no oil reservoir to check like my old mercruiser boat did. Having said that my new boat has given me absolutely no problems at all, whereas my on my old one the first of many warranty claims was one of the legs bearings failing, both brand new boats. Could it be spannerman that over the 16 years you have worked on more Volvo's because there are more of them about.

 

[MapisM]

I am wondering what way to go - Mercruiser or Volvo?

Neither. I'd go for a couple of Ilmor V10 coupled to their Indy drive.
Bound to put a grin on your face just by turning them on, not to mention actually driving the boat!
I'm pretty sure Sonny Levi would approve, too.

 

[Dave_Snelson]

I never really had any serious problems with my twin DP's over 6 years of ownership, but that is down to religious and expensive replacement of parts at the end of every season. I will however confirm spannerman's dislike fo the Volvo legs inability to shake off even the simplist of fishing line problems as the line completely avoids the so-called "line cutter" (ha bleeding ha) and winds itself onto the shaft and destroys the oil seal.

The only reason I got way with it was that I was on my way round to lift out and service at the end of the season, so we noticed the "white oil" goo running out of the bottom of the leg when the boat was lifted.

I do like the very smooth Volvo cup & cone clutch assembly when engaging gear.

I don't like the Mercruiser "drop some cylinders to avoid gear damage" grrrunch when engaging. Although to be fair, I may be out of step with this archane process with later drives - Spannerman, can you confirm?

 

[Spidybot]

Over here, in Scandinavia where Volvo's home market should give them an advantage, Mercs are still very common.

As many boats come from the US (Brunswick) there isn't much choise but even scandinavian manufacturers tend to use or offer Mercs. At the end of the day both Volvo and Merc use the same (petrol) base engines, so the sterndrives might be the thing to put them apart.
Quite different on the diesel scene where Volvo enjoys better reputation (mainly due to their use of 'own' products from bus/truck division) than Merc (known to base more small or midrange diesel series on italian VM engines).


Regarding clutches: Volvo use cones in all drives, Merc uses dog clutch in Alphas and cone in the rest.

Spares and service parts for the Volvo are more expensive, at least in our markets.

 

[lovezoo]

I do like the very smooth Volvo cup & cone clutch assembly when engaging gear.

I don't like the Mercruiser "drop some cylinders to avoid gear damage" grrrunch when engaging. Although to be fair, I may be out of step with this archane process with later drives - Spannerman, can you confirm?

As already mentioned, its only the Alphas that have the dogtooth clutch and you soon get used to the clunk. Incidentally the "drop some cylinders" shift interupt switch only operates coming out of gear when in the water - otherwise you can't get it out of gear as the dogs are so well engaged - this also means the clutch can't slip and there are no cones to wear out and need replacing.

 

[Pennpromo]

Mercruiser V Volvo

I have been told on quite good authority that there is now an issue with drives made in the USA: Due to pollution laws they are no longer allowed to use CFC and toxic based paints. The effect of this is that Mercruiser drives are no longer acid etch primed and the paint falls off.
I have a pair of Bravo 3X drives, two years old and a lot of the paint has fallen off. Boat is kept in the water, use genuine Mercruiser anodes and have Mercathode fitted, (and working).
Where the paint has gone the drives are still grey and unpitted so it doesn't seem to be corrosion just lack of adhesion. Planning to bring the boat out this winter strip off all the paint, acid etch and repaint.
Has anyone else had similar issues ?

 

[spannerman]

Spannerman: can you also confirm that Mercruiser bellows are made of thicker plastic than the Volvo equivalent?[/QUOTE]

Thats absolutely correct, Mercruiser bellows are twice as thick as VP and twice the price!, but they last a lot longer if fitted exactly as per the book, I have had boats in with bellows 5 and 7 years old and bone dry inside, also had boats one year old and leaked as the boat builder didn't do the installation as per the book.

Yes its true I have worked on more VP drives than Merc as there are more of them about, but in the same last 16 yrs we have sold Mercruiser powered boats the whole time and they are being fitted by more and more Scandinavian builders, so they have existed side by side and definitely give less problems than VP, but as with everything its down to correct servicing.
If we got a twin engine VP boat in its always was a very safe bet that one of the two drives would have water in the oil. However the newer DPH-A and DPR-A drives fitted to the D4 and D6 engines seem slightly better but even these have let water in, its because there is no protection for the oil seals on the prop shaft whereas Mercuisers outer seal has a metal shield over it with about .5 mm gap around the shaft which definitely keeps line etc out.

 

[lovezoo]

Thanks Spannerman - at last we have some definitive answers from an expert with hands on experience.

I changed the shift cable on my Alpha 1 Gen II outdrive last year (€70 for the parts). The shift cable boot looked as good as new, despite being 8 years old...

 

[MapisM]

The shift cable boot looked as good as new, despite being 8 years old...

Yup, aside from my previous joke, I read somewhere that the Alpha is actually (by far) the best seller outdrive of all times.
There must be a reason...

Its main problems are that:
1) it can't stand big blocks torque;
2) must be ordered in specific l/h version if required;
3) the gear "clunk" is awful even when you get used to it.

All that said, 1) wouldn't be a problem for the OP since he said that he's using V6 engines, and 2) is just a matter of fitting the proper version on each side.
For 3), my personal suggestion is to fit dual levers throttles.
Aside from the fact that (imho) they're better when you get used to them, they allow a "stronger" operation of the gear lever without the risk of throwing the crew overboard. With Alphas, that actually makes gear shifts smoother.

 

[AndieMac]

my personal suggestion is to fit dual levers throttles.
Aside from the fact that (imho) they're better when you get used to them, they allow a "stronger" operation of the gear lever without the risk of throwing the crew overboard. With Alphas, that actually makes gear shifts smoother.

Agree MM, and quite a natural set-up for those coming from larger boats, with the black and red knobs and levers.

 

[joliette]

Thank you for your thoughts.

I hadn't realised the phenomenon of the Alpha clunk but, never-the-less, the Mercruiser drives seem like a more robust system than the VP drives. My instinct, having read all of the feedback, is that Mercruiser is the way to go. So, now I just need to find a good matched pair of Mercruiser V6s with drives ... Let me know if you hear of any! Thanks

 

[lovezoo]

Bear in mind the Alpha drives changed to the Gen II version in 1991, so if you are looking at second hand Gen II is the way to go. You can also buy brand new clones of the Alpha Gen II drives for £1,650 plus vat.

 

[rubberduck]

I will set up a machine gun on the swim platform & all fishermen vill be shot, hence solving the problem