282 Sailfish fuel economy

[gotafish]

I am the proud new owner of a lightly used 2001 282 Sailfish, (thanks to all the advice I received on my previous post).
So I ran the boat from Seattle to its new home port in Everett and was a little bit surprised that I did not get much below 18 gph doing 22-23k at 3,100 or so rpm, is this pretty much what I can expect with 2 x 250 two stokes?

 

[no problem]

If you email Grady customer service with your year make model and engine info they can probably email you a performance bulletin with all the info from when it was new. You can compare that to what you are getting now to make sure you haven't lost any efficiency.

 

[Tashmoo]

This is the closest thing that Yamaha has posted.

http://www.yamaha-motor.com/assets/prod ... 50txrd.pdf

 

[Grog]

That's about 1.4 MPG, you should be able to squeeze a bit more out. If you up the RPM's a bit and trim then up... How were the seas? Are they HPDI's or OX-66's?

 

[BobP]

Get it up to 4000 RPM.

Don't expect much more, that's it with conventional 2 stroke carb or fuel injection.

 

[RAINMAKER]

With those 250HP FOUR STROKES you should be able to increase your speed alot with just few more RPM's. Run the boat up on plane, trim it out and listen /feel the sweet spot for your best cruising speed and effeciency. I always keep messing until I feel the boat "relax" and I know I'm at optimun then.
Your boat should be easy with all that power on the back.

I get 27 knots at 3900 rpms and 1.5 NMPG with my HPDI's .

 

[BobP]

250HP 4 strokes were not for sale in 2001, I don't believe any Yamaha 4 stroke was.

It was 200/250/300 HPDI or any OX66, period.

 

[RAINMAKER]

My mistake BobP I misread it and thought it was 4 strokes. My bad....

 

[BobP]

Rain, get your HPDIs up to 4000 RPM if the water condition allows, that's the sweet spot per tested data.

I have the 200 HPDI tested data for the Sailfish vs. the F225s- which was removed for their site later.

 

[gotafish]

Thanks for all the advice.
The 250’s are ox-66’s and the seas were calm at the time. I will try to increase the rpm’s on the next test run and adjust the trim.

 

[3rd Day]

I ran a single 250 Ox66 on a previous boat and it really liked 3800-4000 rpms at cruise. Running lower rpms the motor seemed to be lugging. A flow scan may also be helpful.

 

[Desperado]

BobP,

Any chance I could get the HPDI vs. 225 data from you? Thanks!

 

[bc282]

i believe with those engines you should see 1.4 to 1.6 mpg as an average.
F225 or F250 combos will usually yield 1.8 - 2.0 mpg.

start the trim tabs in neutral position (fully up), get the boat on plane without tabs (engine and engine trim only), on plane trim engine and use a bit of tab to position running position, now the important part for fuel economy >>>> trim engines up a little at a time and pausing to watch the fuel flow, speed and rpm. you'll get to a point where too much trim will cause speed to stop increasing, fall off and props can vent (you've definitely gone too too far in your trim). you'll need to bump the throttle back a bit as you trim up to keep the rpms in the cruise range.

you should find that the in smooth conditions you'll have the engines trimmed up pretty far running 35-4000 rpm (cruise).

 

[BobP]

Desperado, I have the sheet home (I hope), will find it and post here.

 

[gotafish]

Yesterday I ran from Everett WA out to Hat Island and back. I (as suggested) ran it at 3,900 – 4,000, and what a difference. Just from the sound of those 2 x 250’s I could instantly tell that they really liked it at that RPM. We were cruising 27-29 knts burning 22 g/hr so not much difference in the fuel economy. Next step I will start playing with the trim on booth the motors and the trim tabs, however the boat sat for 4 years before I bought it so the trim is not working as good as I think it will after upcoming service.

 

[HaleNalu]

Glad to here you felt better about running it. As noted, the 3700-4000 RPM range is where I have always run mine for general cruise.

So- you said 27-29 knots. Average of 28 knots and 22g/hr translates into 1.46 statute mpg. I think you will find that for that year of motors, that is very close to optimal fuel economy. Best fuel economy on the Sound like you were doing is most likely with tabs all the way up, and the engines should be trimmed up until they start to sound different (higher pitched) as the props start to ventilate, then trim them back down. At this level you "should" be running about optimum for flat water.