Fuel usage

[Bubbasboat]

Just out of curiosity, what is your hourly fuel consumption rate?

What year is your motor?

Make/Model?

How many HP?

2 or 4 cycle?

Is motor I/O or Outboard?


I personally am currently running a 1977 Evinrude 70 hp 2 cycle outboard. I am using of average 2 gallons per hour at WOT.

 

[bekosh]

I don't want to know what my gallons per hour is at WOT. :faint2:

 

[redneck joe]

yeah I rarely run WOT.

1979 260 (350 Chevy) Mercruiser at a comfortable cruise of 3200 RPM (23 MPH) about 2.5 MPG.


on the last boat, twin 454's at a comfortable cruise I got .8 MPG @ 16 MPH.

 

[jtmarten]

Still in the process of rebuilding the 460 for the CV23 jetboat, but my previous 23' jet (~310hp, very mild 454) yielded 2mpg at ~3000rpm. The 460 will be ~500hp, so I'm guessing I'll net ~1mpg WOT, so about 65GPH consumption.

 

[jtmarten]

I personally am currently running a 1977 Evinrude 70 hp 2 cycle outboard. I am using of average 2 gallons per hour at WOT.

Think I'm callin' BS on this one. If your speed is 35mph at WOT, you'd net 17.5mpg!?!? Better call Guinness, you just broke the world record for watercraft fuel efficiency.

 

[Bubbasboat]

Think I'm callin' BS on this one. If your speed is 35mph at WOT, you'd net 17.5mpg!?!? Better call Guinness, you just broke the world record for watercraft fuel efficiency.

Where did you get the 35 mph from in your equation? I wish I could get 35 mph!

Maybe I will after the trip to the lake today to do a suggested throttle and idle adjustment. Probably will end up using more fuel.

Been told I'm probably not actually reaching WOT as I had thought. No world record here,

I am further being told I should actually end up using between 6 and 7 gph. with my particular motor. No jet boat here!!!!!

 

[Bubbasboat]

Also, no "BS" here, just trying to put up best available information so that experts such as yourself can help me figure out the truth. Thanks for your help!

 

[bruceb58]

The GPH usage is pretty meaningless without knowing more about the boat and speed it is doing.

Out of curiosity, how are you measuring your GPH?

 

[WIMUSKY]

Just curious what is trying to be accomplished with this topic. Are we trying to resolve something? Or, is this just something asked out of curiosity, like the What Tow Vehicle topic?

 

[Bubbasboat]

Actual run time at what I believed was WOT, measured fuel qty at start and ran tank empty, measured qty remaining in tank (portable 6 gallon tank). My best speed was 23mph(according to my pitot speedo system) when water was very calm at start getting rougher all morning with reduced speeds at times. The boat is a 1974 Glasspar V165, weighs 990# with a 1977 70 hp Evinrude which weighs 212#. Had tree adults on board with 500# give or take, 6 gallons test fuel and 5 gallon reserve can, a cooler full of food and soda and ice and two anchors. slowed to do 4 driver changes ran for 2 and 3/4 hours with basically a quart left in tank when it ran out. Believe my problem to be the WOT presumption, thinking I'm not really getting there as I thought.

 

[bruceb58]

Pretty tough to figure out GPH using your method unless you are using a stopwatch and going pretty much constant speed the entire tank.

I have a fuel flow meter on my boat that ties into my GPS that gives me actual MPG.

i take it you don't have a tach?

 

[Bubbasboat]

Just curious what is trying to be accomplished with this topic. Are we trying to resolve something? Or, is this just something asked out of curiosity, like the What Tow Vehicle topic?

Originally asked out of curiosity, but has turned into a conversation about my boats stated gph fuel usage. OK by me!

 

[Bubbasboat]

Pretty tough to figure out GPH using your method unless you are using a stopwatch and going pretty much constant speed the entire tank.

I have a fuel flow meter on my boat that ties into my GPS that gives me actual MPG.

i take it you don't have a tach?

Is there an accurate (or reasonably accurate) way to measure it since I don't have a flow meter and gps, besides going out and buying them?

 

[Bubbasboat]

I don't want to know what my gallons per hour is at WOT. :faint2:

Nice boat. Don't blame you for not wanting to know you GPH at WOT! Yes I too would :faint2:!!

 

[bruceb58]

Is there an accurate (or reasonably accurate) way to measure it since I don't have a flow meter and gps, besides going out and buying them?

You have to go at a constant speed with no stops and starts with a measured amount of fuel and measure your time. All has to be done very accurately.

Problem is, it can vary greatly with trim, speed, wind, and water conditions.

 

[oldjeep]

20 ft Malibu with a 350HP/350CI v-drive. I don't want to know what my GPH is at WOT either. I fill it when it needs gas and try not to think about it

 

[bruceb58]

I have my MPG info on my GPS. If I am going to do a long run like 30 to 60 miles, I will typically adjust my throttle and trim to max out my MPG. If it's short run stuff, I typically don't worry about it.

 

[oldjeep]

I have my MPG info on my GPS. If I am going to do a long run like 30 to 60 miles, I will typically adjust my throttle and trim to max out my MPG. If it's short run stuff, I typically don't worry about it.

Definitely makes sense if you are covering that kind of distance.

 

[Bubbasboat]

Have tach, just not working, haven't figured that one out yet. Perhaps doing a shorter duration test with less fuel earlier in the day with calmer water would be more accurate. Easier to control factors.

 

[bruceb58]

Definitely makes sense if you are covering that kind of distance.

Also at a place like Lake Powell where places to buy gas are few and far between, you want to conserve as much as possible. The first time I was there with this boat, I ran around all week at a fairly low speed thinking I was conserving fuel when actually, I could have been going much faster to get better MPG.