Merc or Volvo V6

[Tafflad]

I asked for some help a while back ....(new boat spec) and you guys convinced me to go for Duo Prop drive.
My current boat has a Merc 4.3 200hp and the boat is 19'4" hull, 8'4" beam and weighs in at 3,100 Lb. I prop with a High Five for holeshot .... and my use is all about recreational towed sports in salt water. Boat is trailered.
This engine has always met my needs with no issues.
My next boat (FourWinns is likely candidate) is almost identical in length, beam & weight.
Dual Prop drive this time … so will improve holeshot and lower speed planning.
My dilemma is what motor to get ….. Volvo 4.3L 240hp DPS or Mercruiser 4.5L 250 Bravo III
Considerations ..

Mercruiser
Easier access to mechanics & spares
Cheaper parts (may not be true for UK)
Fresh water cooling another $1200
New modern design motor
Lots of concerns on line over Bravo III corrosion (though may not be current issue)
Volume of units sold should have evolved design well.
SeaCore buy-up too expensive – is this a risk for Bravo III

Volvo
Mature design, reliable DPS package
Read that external trim pump increases risk of corrosion (is this true )
Drive is difficult to work on so maintenance costs are higher
Fresh Water cooling as standard
Variable valve timing – better efficiency
Good reputation for salt water longevity


For me I had initially ruled out Volvo as nearest service location is a 100mile round trip …. But in past 10 years only ever had to take boat in for annual service & winterizing (which is a 50mile round trip)

Seen some side by side test reviews that show Volvo has edge on Mercruiser … eg https://www.youtube.com/watch?v=9-0UDMmb2PI

Anybody able to give any advice to help my decision one way or other, either V6 option should see performance uplift from current boat ... 40/50 hp more and duo prop.

 

[Alumarine]

The only comment I can make is perhaps to avoid the Mercruiser 4.5.
It's a relatively new Mercruiser developed engine.
I can't speak to the future reliability or performance of it but spare parts and mechanics that know how to work on it are going to being fewer. At least in the short term.

A 4.3, 5.0. or 5.7 will be easier to get parts and service for in the foreseeable future I think.

That's my off the cuff opinion!

 

[Scott Danforth]

Look at the cooling system on the Merc 4.5 there has to be 200 meters of hoses

there are now about 4 threads for the Merc 4.5 overheating.

I personally would go with the VP with the variable valve timing on the 4.3 (power is the primary reason) over the 4.5 until the bugs are worked out...... who am I kidding.... I would go with the biggest motor that I could get.

as far as economy goes, its a boat.... if you want economy, buy a boat with a sail.

 

[jimmbo]

The New 4.3 is not the same as the 4.3 we have known for years. The new engines are much higher HP, and are making it at 5800 rpm,

 

[Tafflad]

Seems that Volvo has the plus points.
Fully accepting the comments about Volvo over Mer 4.5, Looking at the Volvo performance curves .. in the usable Rev range ... 0-4600 the 240 & 280 are identical in terms of power output.. 280 only really comes into its own above 4600.

I know that in real world use it’s torque that is important ... and again looking at Torque they are the same up to 4600 rpm.




In my watersports use, loads of torque for holeshot, but running at medium revs rather than WOT .... would the 280 be of any benefit.

 

[Scott Danforth]

the difference in the 240 vs 280 is the 280 is allowed to rev to 5800 RPM. same motor, same parts, different RPM limit setting.

 

[Tafflad]

So if I am not going to operate in that rev range linen paying the premium probably not worth it.

 

[Alumarine]

The New 4.3 is not the same as the 4.3 we have known for years. The new engines are much higher HP, and are making it at 5800 rpm,

Thanks for that info. Didn't realize Volvo had changed as well.
Looks like their V8's are new as well.

 

[Scott Danforth]

the VP V8's have been the same LS variants for a while (since 2008 / 9)

 

[Alumarine]

the VP V8's have been the same LS variants for a while (since 2008 / 9)

Didn't know that either!
Saw that they were aluminum blocks and thought they were propietary.
Good to know they're still GM based though.
I wonder who makes the 4.3's for them or what they're based on?

 

[Scott Danforth]

GM powertrain

https://www.gmpowertrain.com/marine.html

 

[jimmbo]

the difference in the 240 vs 280 is the 280 is allowed to rev to 5800 RPM. same motor, same parts, different RPM limit setting.

when I checked the VP site , all the 4.3s were rated @5800

 

[Tafflad]

The performance curves do show a difference, but only above 4800 rpm, the specs do say 5800 on all three V6 models.

 

[Scott Danforth]

when I checked the VP site , all the 4.3s were rated @5800

I stand corrected on the RPM, however its still all the same hardware for all 3 ratings.

 

[Tafflad]

Wonder if all h/ware is the same .... if so then presumably it is just software mapping of the ECU

 

[jimmbo]

Until I see the parts lists for the heads, pistons, valve train and induction, I'm not going to assume it is only mapping

 

[Scott Danforth]

Until I see the parts lists for the heads, pistons, valve train and induction, I'm not going to assume it is only mapping

40CFR - Part 1045 enforcement put a stop to marinizers swapping parts. the EPA requirements still haven't backed off, however the credit program has run out.

 

[jimmbo]

40CFR - Part 1045 enforcement put a stop to marinizers swapping parts. the EPA requirements still haven't backed off, however the credit program has run out.

I'm not familiar with US laws.
I changing a camshaft grind, or the size of the valves, or a change in Intake runner size, to make more power is not 'swapping' parts.

 

[Tafflad]

Until I see the parts lists for the heads, pistons, valve train and induction, I'm not going to assume it is only mapping

The post said all the hardware is the same ..... prompted my Q ..... if any of items you mention are different, then hardware not the same.

 

[Cortes100]

A little late to this conversation but...………...the Merc 4.5 came out in 2015 so it's not that new.
I have a 2016 with the 200hp version of the 4.5L. All I can say it runs great, very quiet, good on fuel, has lots of power through out the whole rpm range. No complaints with performance. Yes there are a few hoses and wires and still learning on some of the maintenance procedures compared to the old GM 4.3. But overall happy with my choice.