Gas Mileage Guestimator

[flydoc]

On a full tank 40 gallons, Calm seas, ballpark what should my range be?
I've always stayed within 5 nm of my ramp and always try to maintain a full tank before I go out. But I wish to venture out a little further and want to make sure I can run and gun along the coast for albies and have fuel for the return. I have and older 2 stroke carbed 115 yamaha and an 1800 cc both from 1999. :?:

 

[Outta Here]

I used to run an 18 Parker/115-2 Yamaha w/4 people from 20-app 32 statute miles offshore. Almost always rough, slow trolled all day. I can't remember the milege, but fuel was never a problem.

Rule of thumb is 2 mpg for most all boats.

Yamaha has pulled their performance bulletin for this combo. I'll bet a request to Parker would get you one.

 

[J.A. Veil]

My previous boat was a 17' Scout with a Yamaha 90-hp carbureted 2-stroke motor. This was a light boat, but I still rarely got above 3 mpg. I think an estimate of 2-3 mpg is fairly good.

Interestingly enough, my current 23 SE with a 200-hp HPDI motor gets nearly 3 mpg, or about the same as my old boat. The hull is 3 times as heavy and the motor is more than double in hp. That is the beauty of the HPDI compared to a traditional carbureted motor.

 

[Outta Here]

Go figure :?

I went from 115-18' to 23SE-200 HPDI and don't remember much if any fuel difference. 200 HPDI hardly used any oil.

 

[Outta Here]

On a full tank 40 gallons,
quote]

Woahhhhhhhhh Thare.........You got 40 or 60 gallons?

 

[flydoc]

They boosted up the tank size in 2000 to 60gallons.
The replies have been very helpful though.
I'll probably put about 30 miles total on so I should be ok.
Sea Tow insurance is in effect!!

 

[MK1GRAY]

One way to help with the question of gas mileage is to install a "FLOSCAN" gauge. This will help you find your optimum GPH for cruising.

Once I get my 1800 back in the water i'll let you know what I get.

 

[Parkerman]

I alwasy hear that 1/3 of a tank out, 1/3 of a tank home and 1/3 of a tank JIC.

 

[Jersey Jim]

I just ordered the Northstar F210 Fuel totalizer that I saw posted here months ago. I recommended it to a friend and he got one first about a month ago. I think it used to be called a Navman 2100. Anyway, the point of my post is, Boater's World has had them on sale "while supplies last" for only $99 instead of $149. The store manager I phoned said they were out and that the internet site is a different franchise. The online store still had them and mine should arrive today. With the extra weight of 60 gallons and potential gas theft, I see no reason to keep over 300 miles in my tank. I've already been out on 4 trips totaling 150 miles and still have over a half tank. Since I plan to keep a partial tank, then the totalizer will be beneficial to know what has been pulled out of the tank. Does anyone have any accuracy issues/comments about the F210?

 

[Megabyte]

Does anyone have any accuracy issues/comments about the F210?

I have the Navman 2100 version of that unit and it has been very accurate for the past 3 years.

 

[Jersey Jim]

Thanks Kevin. I'm about to cut it in this morning. However, the recommended 20" distance from a radio rules out mounting it where I really wanted to, and would be most visible. Just how far did you mount yours from a transmitter?

 

[Megabyte]

Thanks Kevin. I'm about to cut it in this morning. However, the recommended 20" distance from a radio rules out mounting it where I really wanted to, and would be most visible. Just how far did you mount yours from a transmitter?

I've never measured, but the photo below will give you a visual.

The Navman 2100 is just off the lower left corner of the Garmin chartplotter.
The Icom 502 is directly under the binnacle.

FWIW - I've never heard of interference between a fuel meter and a VHF.

 

[Jersey Jim]

Kevin, thanks for taking the time to post the pic. I think that the reason they recommend the 20" minumum distance is to prevent transmitted RF power from interfering with the fuel monitor, instead of the opposite, the gauge interfering with receiving a weak signal. Just to be safe, prior to cutting the hole I powered up the transducer and gauge via cigarette lighter plug. I placed the gauge very close to the radio and transmitted high power on an unused channel. No change in operation appeared to occur. I also tuned the radio to the weakest WX station and then unplugged the fuel monitor to see if the close proximity to the radio caused decreased receiver sensitivity. It made no difference. The final test was to place the transducer cable within a couple inches of the actual antenna while transmitting. This extreme condition caused the gauge to beep and reset as it does on a power-up condition. Armed with these results I made the hole within 10 inches of the "cut-in" and immovable radio and all worked fine.

Have you notice what flow-rate (gph) your OB indicates at around 700 rpm idle? Mine reads just under 0.2 and sometimes 0.2 gph on my F115. This is below the transducer's minimum flow of 0.4 gph. I don't think I'll be recording accurately below 1000 rpm. At that flow, what's a quart per hour anyway going to amount to for a few minutes idling here and there.

Thanks again for the reply. Yours was the only reply prior to my install. I've been waiting for days for advice before installing this weekend (on another thread).

 

[Megabyte]

I would have to go find the documentation for my Navman... but as I recall, the transducer/receiver could be re-programmed for the 'lower flowing' 4 strokes (versus my 225 Yammi OX66).

Check your documentation, and I think you will find that reference. :wink:

 

[Jersey Jim]

Kevin, All that Northstar provided was a method of calibrating for closer accuracy. It was simply to use a known amount of fuel (easier said than done), and if the trip or total gas used value does not match, then simply incriment of decriment the displayed value. Apparently the proper scaling factor is applied based on what was used and what's displayed. This algorithm compensation will only work so far, as the internal turbine of the transducer must be physically tailored for one range or another.

It boggles my mind how little gas actually flows through the fuel line, even at WOT. My F115 has metric ID line, very close to 5/16", not 3/8. Even with this thinner line, and a rate of 0.2 GPH at idle, the gas moves through the line only 1 inch every 6 seconds! No wonder the transducer isn't rated slower than 0.4 gph. (3008 inches of line for each gallon).

Thanks for looking that up.

Jim

 

[channel_surfer]

At a dead idle (600R) my F210 will read very low, like 0.1 or 0.2, then spike up to about 1.0, then slowly trail off back to 0.1-0.2, again and again. Once up to about 800-1000R, it shows a stable reading of around 1gph. I've had two F210's (first one transducer went after about a month of use, replaced) and both showed the same behavior at idle with the Yam F225. I'm thinking maybe at idle the fuel pump only pressurizes the EFI system in 'bursts' which is what I'm seeing on the meter.

 

[Jersey Jim]

Steve, thanks for the insight on how the F210 may work with a larger O.B. I found the reading to be erratic at idle when the air bubbles were purging out of the recently primed fuel separator. Also, squeezing the primer bulb affects how stable the flow reads at idle. I mounted the transducer vertically as recommended in order to pass the initial air bubbles through. My buddy and I installed them on our boats at the same time and we are equally impressed with them. Although your fuel may be used in "bursts" did you find the totalizing to be accurate?

Also, when the transducer failed, was it all at once or intermittently?

Jim

 

[channel_surfer]

Fuel use is almost 100% accurate as far as I can tell. I did calibrate it with a 5 gallon jerry can and it was about 0.1 gallons off after the 5 gallon burn.

One day the meter worked, next day it was reading about 1/2 what it should (like 6gph at 4600R) and next day after that it was dead, 0.0GPH. The replacement seems fine about 80 hours on it now.

 

[pelagic2530]

kevin, or any of the other guys, can you give me a more detailed description of how this unit works? like how it mounts, what exactly it measures, how hard is the install, etc? it says its a one engine thing, could i potentially install two, one per side? ive been looking for a way to better manage my fuel and $200 sounds pretty cheap for that. thanks

 

[Megabyte]

It is pretty simple really. You have a 2" round gage that goes in your helm, and a fuel transducer that goes in your fuel line after your fuel/water separator, and before your motor.

The fuel transducer has a wire attached to it that attaches to the instrument on your helm, and all you have to hook up is the power lead.

Make sure that the fuel transducer is mounted vertically as recommended, and you are good to go.

Installation took me all of 30 minutes, and that included drilling the hole in the helm.
It is a simple install.