2000 340 DA Optimal cruise for fuel economy

[Art Macasinag]

Hi Everyone,
Just got a 2000 340 Da with twin 7.4 310HP mercruisers. I was wondering if anyone could share their
expertise on the best cruise speed/rpm for optimal fuel economy on these boats? I got approx. 400 hours on each with good compression @ around 175-180.
Thanks, Art

 

[VinceR]

SEA RAY 340​

2001​

PERFORMANCE​

TWIN 454 MPI​

310 hp​

​

Speeds by GPS
Fuel Flows by computer connected to engines.

RANGE IS 215 GALLONS

RPM MPH GPH MPG RANGE

700 3.9 2.0 1.95 419

1000 6.0 3.6 1.66 358

1200 6.8 4.4 1.55 333

1500 7.9 7.0 1.13 242

2000 12.4

2500 18.6

3000 16.9 24.0 .70 150

3200 20.5 26.6 .77 164

3400 24.1 30.6 .79 168

3500 25.0 31.0 .80 172

3600 26.4 33.4 .79 170

3800 28.0 34.8 .80 172

4000 29.5 38.0 .77 164

4300 32.6 47.6 .68 147

 

[Art Macasinag]

Thanks, Scott... Thanks Vince.
I appreciate the info.
The tabulated info @ various rpm ranges is really awesome !!!
Cheers!
From a newbie, Art

 

[jim_m5]

Vince,

Great table. i see infor at 2000 and 2500 rpm's missing. where can I find those?

 

[VinceR]

I need a clean hull to get those. I have a load of grass on the hull now. I am too lazy to put it on a trailer and power wash. I think those are the worst RPMs you can use. The boat is not on plane and it is pushing max water.

 

[HUMPH]

Did you get the "R&R"?

 

[dpmulvey]

What size are the tabs?

 

[Art Macasinag]

Hi 2K Wingin' It,
Yes, I did get the R n R.

Hi David,
Forgive me for not being sure what you mean by the "tabs".
If you mean the trim tabs, I'm not sure how wide they are.
They are Bennetts.
Thanks!
Art

 

[VinceR]

My tabs are the ones Sea Ray installed. They need to be larger.

 

[rcknecht]

SEA RAY 340​

2001


PERFORMANCE


TWIN 454 MPI


310 hp​

Speeds by GPS
Fuel Flows by computer connected to engines.

RANGE IS 215 GALLONS

RPM MPH GPH MPG RANGE

700 3.9 2.0 1.95 419

1000 6.0 3.6 1.66 358

1200 6.8 4.4 1.55 333

1500 7.9 7.0 1.13 242

2000 12.4

2500 18.6

3000 16.9 24.0 .70 150

3200 20.5 26.6 .77 164

3400 24.1 30.6 .79 168

3500 25.0 31.0 .80 172

3600 26.4 33.4 .79 170

3800 28.0 34.8 .80 172

4000 29.5 38.0 .77 164

4300 32.6 47.6 .68 147

Vince, I find when my 340 is lighter that I get better fuel economy between 3300- 3400 RPM... My numbers match yours with a full load... Have ever compared a light (1/4 tank of gas) compared to heavy???

 

[HUMPH]

Hi 2K Wingin' It,
Yes, I did get the R n R.

My wife and I looked at it and decided not to make an offer then changed our minds and you had already had your offer accepted. My wife keeps referring to the R & R as "her boat"! I am hoping to find out about my offer on a 2002 320 from the same people this week.

 

[VinceR]

When we get to about 1/2 tank of fuel our speed increases at 3600 RPM about 10% and so does the fuel mileage.