Fuel use 320 DA w/6.2 Vdrives?

Groucho

Well-Known Member
Jun 11, 2008
1,614
Albany/Lake George NY
Boat Info
2004 320 DA
Engines
6.2 V-Drives
Almost have my 2004 320 at my dock (Buying). Just wondering....We spend most of our time around 7-8 knots..At least we did with my prior 2006 290. That was the point before pushing a lot of water. It used about 7-8 gph.
Does anyone with a similar setup have some stats they could share with me?
What speed will I be at for slow cruising and max economy?

Awhile back someone had stats on fuel flow at different speeds..(I used to be hanging on the 290 section).

Thanks in advance!
 
Love or hate this company boattest.com, here is the Boattest review with some stats for you.

Why hate? They almost never disclose bad features. Reviews are overly positive for all brands and all boats. However, I’ve found their performance data to be factual.

 
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Almost have my 2004 320 at my dock (Buying). Just wondering....We spend most of our time around 7-8 knots..At least we did with my prior 2006 290. That was the point before pushing a lot of water. It used about 7-8 gph.
Does anyone with a similar setup have some stats they could share with me?
What speed will I be at for slow cruising and max economy?

Awhile back someone had stats on fuel flow at different speeds..(I used to be hanging on the 290 section).

Thanks in advance!

Measured by boattest.com with fuel flow meters, 2002 320 Sundacner with 2 x 300-hp MerCruiser 350 MAG MPI

From memory, the boat you are considering for purchase has a Merc 6.2L V8. I assume you know these motors began life as a 5.7L GM small block. Mercury “strokes” the engine, meaning they change internal parts to make the pistons go up and down for a greater distance, called stroking.

Stroking is the opposite of boring, which maintains the up / down piston travel, but increases the size of the piston hole. Boring can improve torque, stroking can increase max RPM, possibly resulting in greater horse power.

As factory stroker motors go, Mercury did a commendable job with their stroked design. The motors reliability is on par with the 5.7/350 motor. They increased maximum horse power by 20, from 300 to 320. Independent testing has shown those bonus 20 ponies in the vintage 6.2L Merc all run around at max RPM.

Only downside I can think if is this modification did not increase the torque one bit. So any 320 Sundancer owner that thinks their boat with its 6.2 planes faster / easier/ better then one with a 5.7 is not using factual data. Top end speed will improve with the 6.2. Engine block size is identical.


My opinions, offered in hopes of helping. None of these above stats or statements apply staring in 2010 or newer when Mercury stopped using General Motors blocks and started casting their own sterndrive engine blocks at plant #17 in my hometown of Fond du Lac, Wisconsin with lost foam casting technology. I always recommend getting several opinions, then make your own decision.


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Once you are into a twin engine 30+ foot planing cruiser, you might as well stop worrying about fuel economy. Just run the speed you want to for the plan for the day and the water conditions. If you are spending money on fuel, you are using the boat, and that is a good thing.
 
Once you are into a twin engine 30+ foot planing cruiser, you might as well stop worrying about fuel economy. Just run the speed you want to for the plan for the day and the water conditions. If you are spending money on fuel, you are using the boat, and that is a good thing.


I hear ya. I was kinda spoiled as my prior 2006 290 had a single 8.1 engine...yup from what I hear SR made a couple of these to test. It was "ok". Once you got used to docking with a single it was easy unless it was windy. But in 631 hours I put on no hard dockings were had.
The single was not that much better on fuel though than twins. I was fortunate to sell it...I bought it as a leftover in 2008.
 
Almost have my 2004 320 at my dock (Buying). Just wondering....We spend most of our time around 7-8 knots..At least we did with my prior 2006 290. That was the point before pushing a lot of water. It used about 7-8 gph.
Does anyone with a similar setup have some stats they could share with me?
What speed will I be at for slow cruising and max economy?

Awhile back someone had stats on fuel flow at different speeds..(I used to be hanging on the 290 section).

Thanks in advance!

Why bother with a twin engine express that can plane and run 25+mph - look at a mainship 34 express (or similar) - can even get one with a hardtop - it can still run in the high teens when you need to, but it is WAY more efficient and would require WAY less maintenance - two gas motors shoved in a comparatively tiny bilge are tough to work on and expensive to maintain when you really don't intend to "use" them
 
Why bother with a twin engine express that can plane and run 25+mph - look at a mainship 34 express (or similar) - can even get one with a hardtop - it can still run in the high teens when you need to, but it is WAY more efficient and would require WAY less maintenance - two gas motors shoved in a comparatively tiny bilge are tough to work on and expensive to maintain when you really don't intend to "use" them

I like your thought process.

Identify your intended boat use then get a boat that’s intended for that use.
 
Why bother with a twin engine express that can plane and run 25+mph - look at a mainship 34 express (or similar) - can even get one with a hardtop - it can still run in the high teens when you need to, but it is WAY more efficient and would require WAY less maintenance - two gas motors shoved in a comparatively tiny bilge are tough to work on and expensive to maintain when you really don't intend to "use" them


Sounds like a good idea, but we are on a lake 32 miles long and 3 miles wide at it's widest point. To find one of those....that will fit at a residential dock...and freshwater would be very unlikely..I do appreciate the idea though.
 

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