F250's on my '92 Marlin Fuel Burn

downtown · Nov 29, 2011

Just put on two 2006 F250s with 200 hours on my 92 Marlin. Replaced the OX 66s.

I'm interested in the fuel burn on similar set-ups.

I haven't really had to chance to get out, but I took it for a quick spin and what a difference.

Thanks in advance for any feedback.

Gman25 · Nov 29, 2011

I get 1.2 MPG 2-3 ft seas... Less with a loaded boat in sloppy seas.

'05 300 Marlin F250's

Tuna Man · Nov 29, 2011

I get as bad as 1.0 mpg in heavy seas when the boat is loaded with gear, regardless of what my cruising speed is. With a relatively light load I was able to get 1.5mpg in 1 foot seas most of this past weekend. At best I get 1.6mpg in calm seas with a light load. (note, that this is statute miles per gallon, not nautical mpg)

Since your boat is a little lighter than mine and has a slightly shorter running surface, I suspect you will do at least as well. The only potential problem I see is since you do not have the extended runnning surface the boat may 'squat' a little when you take off but I doubt this will be a problem once on plane though. Enjoy your 'new' boat!

Gman25 · Nov 30, 2011

Scott 1.6?? WOW!! I never got better then 1.4 which is VERY rare(usually no water and low fuel)..We just reciently went offshore on a wreck trip..Ice gear and 5 guys in 3-6 ft seas I was getting .8 MPG.. But I always keep the fuel and water full.What props are u spinning?

'05 300 Marlin w/F250's

Tuna Man · Nov 30, 2011

I am swinging 15x19 four blade Powertech props. Very happy with the performance, in most conditions we can run from 3800 to 4600 rpm and get at least 1.3mpg. Even at short full throttle bursts we still get at least 1.0mpg. Top speed was 46mph (at 5700) over the weekend with a four man crew and 70 gallons of fuel, fishing gear, water and four nice striped bass.

Tucker · Dec 1, 2011

1.3 mpg at 4600 RPM?? I'm checking into these powertech props. Different rig and engines than mine but that is remarkable efficiency. What's your speed with all that gear and people??

seikialice88 · Dec 2, 2011

Tucker said:
1.3 mpg at 4600 RPM?? I'm checking into these powertech props. Different rig and engines than mine but that is remarkable efficiency. What's your speed with all that gear and people??

i don't understand the question.

Tuna Man · Dec 4, 2011

I think Tucker is interested in the propellers I use. I posted the numbers when I swapped to Powertech a few years ago, they perfrom quite well. I am especially happy with the fact that I can cruise at such a wide range or rpms and achieve decent economy.

Gman25 · Dec 5, 2011

seikialice88 said:
Tucker said:

1.3 mpg at 4600 RPM?? I'm checking into these powertech props. Different rig and engines than mine but that is remarkable efficiency. What's your speed with all that gear and people??

Click to expand...

i don't understand the question.

:uhm......It sounds like he wants to know how fast hes going at 4600 RPM's while getting 1.3 MPG ..

'05 300 Marlin F250's

Tuna Man · Dec 5, 2011

Oh, I guess I need to read a little better before responding. Did not want to derail the thread.

Here are my performance numbers:
RPM SPEED (MPH) Tabs GPH MPG
600 3.3 - 1.4 2.36
1000 6.1 - 2.5 2.44
1500 8.3 - 3.7 2.24
2000 9.1 Full 6.0 1.52
2500 13.0 Full 8.4 1.55
3000 15.0 Full 10.8 1.39
3500 25.4 - 15.1 1.68
3800 29.0 - 18.4 1.57
4000 31.1 - 20.0 1.55
4200 33.0 - 21.9 1.50
4400 34.4 - 24.6 1.40
4600 36.3 - 25.7 1.41
4800 38.0 - 28.2 1.35
5000 39.7 - 30.6 1.30
5500 44.0 - 41.5 1.06
5700 45.3 - 44.5 1.02

Test Date: September 5, 2010 77 degree air 78 degree air 1’ seas, Barnegat Bay NJ
Load: four people, 90 gallons gas, 15gallons water, ~200 lbs tools and gear bottom paint
POWERTECH 15 ¼ X 19” OFS FOUR BLADE PROPS - COUNTER ROTATING
2006 GRADY WHITE MARLIN WITH MOST OPTIONS (no generator)
2006 YAMAHA 250 FOUR STROKE OUTBOARDS (max rpm 5500-6000)

Tucker · Dec 6, 2011

Well there you have it downtown. I'd be checking into those Powertech props that tunaman is using; though I'd be a little concerned that the engines are not reaching max RPM. Betcha with a light load they would get up there. He didn't mention motor trim. To achieve max speed I have to trim just below cavitation to get a heavy bow up. Do you need to do that with the heavier 4-strokes? There is so much speculation about performace differences between full running hulls and the older style. Be interesting to see a comparison.
Tunaman what size props did you replace? How did the Powertech guys determine that the 4-blade would perform better?

downtown · Dec 6, 2011

thanks, guys. i have mercury props, just redone. i will get you numbers next time i'm out there. hope it's this weekend. if not, in the spring.

Tuna Man · Dec 6, 2011

I used to spin Yamaha SWSII 15 1/4 (or is it 15 1/2) x 19" ss props. I did a lot of research and ended up speaking with Ken at Propgods, together we agreed on the Powertech OFS. The Mercury Rev 4 have as good or better reputation, but they were also about 1.5 times the cost. For the record, the old props would spin to 6000 rpm with a similar load. Maybe over this winter I'll finally raise the engines one or two holes.

Downtown, lt us know how you make out.

Tucker · Dec 7, 2011

You guys with the Marlins have buried cav plates? Mine are, with full running hull and light engines.

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F250's on my '92 Marlin Fuel Burn

downtown

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Gman25

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Tuna Man

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Gman25

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Tuna Man

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Tucker

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seikialice88

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Tuna Man

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Gman25

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Tuna Man

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Tucker

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downtown

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Tucker

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