265 Gas Hog???

[Salinity Now]

Hello All, still enjoying the trials and tribulations of learning the new boat, had a bad ignition coil not firing a cylinder last time, problem solved and power is back....but......I seem to be burning ALOT of gas, port motor (same as one with bad coil) uses about 30% more fuel as per flow meter than stbd.

Smokes more too, oil rod was about 1/3 off the stop at idle position, adjusted that to see if it improves.....no real noticeable change IMO.

Someone suggested Low Pressure Pumps, gonna try that this week, apparently you can disconnect them from the block housing prime the bulb and see if fuel leaks out? Im not positive what the LP pumps are supplying, gonna have to trace out the system more this week to really understand, but at $56 a peice, I dont wanna have to replace them for no reason.

As for fuel #'s does this sound right? (Twin 2001 OX66 250's)

Today at lake....ran 26.5nm (per GPS).....burned 24.9gal (according to Yamaha Guage, could be off....unsure of accuracy at this point)....so that would be 1.06nm/gal. That seems pretty bad IMO, I typically cruise at 4000RPMs roughly 26gph (combined) but now all of a sudden Im running about 30GPH cause the stbd is steady at 13gph and port is about 16+gph.

Boat had me and 2 teenagers, probly 1/2 fuel and full water, very light gear, no canvas.....granted I saw 48mph which was nice, but Im looking for FUEL ECONOMY not speed.

How do my numbers compare to other owners? I was expecting an easy 1.5 not 1.0.....?

 

[Salinity Now]

Pulled all 3 low pressure pumps on the motor this morning, found one leaking with pressure via primer bulb. Hope that solves the higher fuel consumption, but definently curious to how other 265's run as far as fuel economy avg #'s etc.

Thanks for any info.

 

[Bob's Cay]

if you were running her in the lake (Lanier?) remember you will not get the same performance numbers you will get in salt water. Salt water is more dense and it takes less of it to float your boat than fresh water. I know my boat sets deeper in the water in Lanier than saltwater.

 

[Salinity Now]

Very good point about the fresh vs salt, but the problem I'm noticing now is the port motor is using more than the stbd, I'm hoping it was just this Low Pressure pump.

I've using the boat at Hartwell vs Lanier Bob, it's 35miles vs 70!!

I kinda take for granted how nice it is to mess with the motors and be 200 yards from the ramp to go test em vs having to ride all tue way to the lake.......but it's also nice to be able to work on the boat in your back yard vs outta the pick up truck. I need to move to the coast vs just work there!!

 

[HMBJack]

Both engines should consume the same amount of fuel (more or less). So I think you're on the right path examining the LP fuel pump. I kept very good records when I owned my 265 with F225's. I averaged a solid 1.5 statute MPG. Sometimes when I was light on fuel and crew weight, I'd reach 1.8. When I was heavy with fuel and ice (tuna trips), I'd average 1.3. Converting to nautical MPG puts my average to 1.3 nMPG. With your two strokes, you're not too far off. Might one of your fuel filters be clogged or due for replacement? Might your injectors be gummed up? I add a can of Sea Foam to my fuel filter when changing it to apply a rich brew of injector cleaner (can get Sea Foam at any NAPA Auto Parts). Good luck with it. The 265 is probably the best boat ever built by GW.