fuel flow meter

[keyscapn]

I put a Lowrance LMF 200 gauge in my boat with a fuel flow metering system. The reason I did this is because the regular fuel gauge never seemed to work properly. (Actually, I've never had an accurate fuel gauge in any boat I've owned.) This at the suggestion of someone on this list, whose name I've forgotten. To that gentleman I wish to say thank you and I'm sorry I forgot your name.

Because the old gauge never went above 3/4 full, I assumed the 40 gallon tank was mounted bow down. That may not be the case. The LMF 200 not only measures fuel flow but gallons used and fuel remaining. I filled the tank and set the gauge to zero. So far I've used 32 gallons and still going strong. I'll know my tank's capacity when I run out, hopefully not in some busy channel. I'm carrying two jerry cans of fuel for when that happens. I'm also carrying a fuel barb to replace the paddle wheel in case it clogs with sediment from the tank bottom.

One thing I've noticed is my fuel flow at different RPMs is not as low as I thought it would be. I have only a 22' Panga.com with a 90 E-tec. At WOT I'm doing 29 knots and burning 7+ gph. That a bit disappointing when I read about 26' pangas with big engines doing 30+ knots and burning 4 gph. I'm wondering if any of these claims are verified by a fuel flow meter. At 20 knots, my normal cruising speed, I'm burning about 3.5 gph, a pittance compared to my old boat, a 30' inboard. I'm satisfied with that since normal sea conditions where I live dictate a comfortable ride is usually between 20 to 24 knots. At my age I don't enjoy the boat going airbourne. The boat can take it; I can't.

Finally, I really like the info this gauge gives me. Setting up the Lowrance network needed for it to work was very easy. Unfortunately the LMF 200 is NMEA 2000 and doesn't talk to my old GPS which is NMEA 0183. That prevents it from doing mpg and range calculations. In the future any electronics I buy will be NMEA 2000 compatible. Still, it's nice to know I won't run out of gas.

[andros]

Great report. One thing i always tell my customers when selecting a motor is that fuel efficiency comes from having the right power for cruise not WOT. There is a carefull balance between too much hp an too little.

Even still 7 gph is pretty good at that cruise with a 90. Very impressive as a matter of fact. I say this because the 90 is working pretty hard. The guys posting about the 4 or less gph on their 26 are talking about the diesel motors.

our 26 averages about 8.5 gph at cruise, but it's mainly due to two factors.
1) properly matched horse power (less than 225 hp would actully increase gph used)
2) hull design and the porta bracket (engine jack) set up

Just curious what will your boat do WOT and what is burn rate?

[keyscapn]

When the boat was new I got 31 knots at WOT. I didn't have the fuel meter then so I don't know the burn. I've since added a bimini top. bottom paint, coolers and loaded the front compartment with a scuba tank, weight belt and assorted other gear. The most I can get out of her now is 29 knots with a burn of about 7.5 gph. The gauge is very sensitive with the gph rising and falling as the sea surface conditions change.

One thing I forgot to mention in my post is my boat is a Super Skiff. a very basic, no frills model. It has no live well, no leaning post and a splatter coat instead of a gelcoat interior. I suppose that makes it lighter than a more finished boat.

[edsmith03]

Just a couple quick notes.

I had the LMF and EP-10 configuration on my boat (26' Angler panga with twin 90 HP Optimax motors) and on first install, it was WAY off... Just make sure you've gone through the calibration sequence to be sure that the fuel flow is accurate.

With a fully loaded boat (fuel fuel, three adults, 200 qts of ice, bait, etc. etc.), at cruise (28 mph and 4000 - 4200 rpms), I'm getting between 2.7 and 3 mpg on my boat (depending on sea conditions, current, etc.). That's verified with Smartcraft gauges (which are MUCH more accurate than I could ever get the Lowrance stuff to be). I don't think even the diesel pangler is getting 4 mpg at 30+ mph...

[jack]

with the price of fuel now, i dont think anyone runs their boat at wot,
unless they dont know how much more juice that last 1000rpm burns
but wot figures gives a good idea of the set up, but arent comparable to someones else cruise speed

with the 22' a 70hp is 30mph @ wot, a 140hp is 50mph @ wot
100% more hp for a 66% increase in speed

if people are happy with a speed of 20-25mph, i think, it would be better with a 70hp than a 140hp
i find mine well balanced with a 70 and i am speed limited by our average conditions here
also, the skegs on mine give lateral drag so its prolly not worth putting on more than 90hp

as with all boats..more speed = more drag..more hp ..more fuel
till you reach terminal hull velocity

if i want a softer ride and better fuel numbers..i slow down

[keyscapn]

Thanks for the tip, Ed. On further review I see I didn't follow the configuration and calibration sequence properly. So I guess it's back to square one. I think my LMF gph numbers are inaccurate because when I was doing it without the LMF / EP-10, just filling the tank before a trip and filling again after and measuring the gallons it seemed the fuel consumption was remarkably low. I guess this is a case where RTFM (read the f***ing manual) applies. Thanks again for setting me straight. Jeff

[trponhunter]

I've owned a pangler with a 225 four stroke and an andros tarpon26 witha suzuki 250 four stroke. Both boats burn 8 or 9 gph at around 30 mph. Both are from a fuel flow meter and gps.

[keyscapn]

edsmith03 said:

on first install, it was WAY off... Just make sure you've gone through the calibration sequence

You are so right, Ed. I filled my fuel tank expecting to pump in 32 gallons and it only took just under 21. On those 21 gal. I rode 95.6 nautical miles per GPS trip meter. So the fuel economy is better than I thought, 4.5 nmpg; the bad news is the LMF readings are way off. My attempts to reconfigure and recalibrate are frustrating. The screens on the gauge don't match the manual. Did you have this problem? I'm thinking I should reset the whole thing back to factory settings and begin again. Anyway, once you got your LMF / EP-10 up and running, how accurate would you say it was?

[edsmith03]

keyscapn said:

once you got your LMF / EP-10 up and running, how accurate would you say it was?

Honestly, I never got it up and running accurately. My boat has twin engines, and the twin engine setup procedure is rediculous. You basically have to run each engine for 5+ hours independently to calibrate it accurately. That's why I went with the smartcraft gauges. They cost a lot more, but last time I filled up, they were 1/10 of a gallon off of what it took to fill up the tank....