Fuel Mileage for sailpro 6hp.

[waterwheels]

Hey,

Does anyone have any idea how far or long I can expect to go on the standard 12Litre (3 gallon) fuel tank on my Eclipse with a 6 hp 4 stroke sailpro?
I have a canal trip coming up and will be motoring some 35KM  (25 miles) between fuel stops. Don't see this being a problem but wondered it I need to bring a spare tank for comfort.
I have never motored far enough to get an idea on mileage........much prefer letting the sails do the work.

Thanks for any input.

Don
Living Water.

[Tom L.]

Read this thred. May answer some questions.  http://cpyoa.geekworkshosting.com/forum/index.php?topic=8232.15

[Shawn]

Full tank should be plenty. Believe the Tohatsu is rated at 1/2 gallon an hour at wide open throttle. You will probably be cruising around half throttle where the engine will be much more efficient and moving around 4-5 knots. If you want to feel better about it bring along an emergency 1 gallon tank... just in case.

Be sure to time your trip with the tide (if applicable) and you will get there sooner.

Shawn

[Vectordirector]

Hi Don,
Shawn seems to have it right:    from the Tohatsu Germany site: http://www.tohatsu.de/outboard-info/MFS6CS-SAIL-PRO/56?PHPSESSID=7629ded646e1f4fb16881b8ac775115e  which specs 2 litres(roughly 1/2 gallon) per hour @ full throttle.  Doing the math,  if hull speed is 5 kts, at full throttle the motor would consume 2 litres to go 5 miles.  That is roughly 10MPG.  1/2 throttle on my 6HP Suzuki will get my boat to hull speed in calm water.  Anything more and it is just more noise and more fuel burned.  YMMV depending on wind, waves, current, etc.  Another interesting tidbit:  When I put my boat away last year, I unhooked the fuel line with the engine running.  It ran for about 15 minutes at just above idle until it died from fuel starvation.  They really do sip fuel.  My engine is 10 years old, the newer ones are probably even more fuel efficient.  The thread posted by Tom L.  also has some good information. 


I can tell you that when I motor out and back in from my dock, 4miles @ 1/2 throttle, about 30 minutes total run time, my Suzuki 6HP 4 stroke uses less than a quart of fuel.  So that is at least 16 MPG.  HOWEVER, and I don't think this has been addressed:

You may have 3 gallons on board, but how much is actually usable?  I ran out after motoring out a few months ago.  The tank had "oh, it feels like plenty" in it so off we went.  The motor died with at least a quart left in the tank.  I could pick it up and feel quite a bit in there sloshing around.  They just can't for some reason, be run down to fumes like a lawnmower can.   I think it is because of the way the pickup inside the tank is designed.  Your tanks may be a different design, mine are Suzuki.  Called Sea Tow and got towed in, never thinking that I had ran out of gas as there was still at least a quart left in the tank.  I thought the motor had died and for some reason, I couldn't get it restarted.  I of course, didn't have the other tank on board.  Not good.  Back at the dock, put more gas in the tank, and bingo, fired right up.  Lesson learned.    Now, I always have two 3 gallon tanks on board.  I'll run one down to about 1/3 full, then switch to the other one.  Once that one is down to about 1/3 full, I'll fill the first one up, switch back to that one, rinse repeat.  This gives, at minimum, a 1 gallon backup at all times.   Works great.  Keep in mind I'm in Florida and I can get out 3-5 times a week and go through a tank in about two weeks.  If you don't use the motor as much as I do, having fresh gas becomes a factor and may result in using a different system to always have enough fresh gas available.  This is my first boat with an engine, so I'm learning as I go. I've also heard that it is easier to pick up dirt in the bottom of the tank by draining the tank down, which may clog up the carb.  Luckily, I didn't have that problem.   So now I never run it less than a 1/3rd of a tank.  As a test you could run yours until the engine dies and see how much is left in the tank.  Might be good to know.  If I remember my aviation ground school, it isn't how much is on board, it how much is usable that is important.  Airplanes have two numbers, capacity, and usable.  One is more important than the other.  Guess which one. 

25 miles at 1/2 throttle shouldn't be a problem.  As Shawn said, I would just carry a small backup 1-2 gallon jug you can use to fill up the big one if you need it between fuel stops.  Takes the worry out, easy to do, and doesn't add much weight.   Oh, and do let us know what you find out.  We need more data on this.  


Good luck on your journey,

Vectordirector

[waterwheels]

Thanks for all the info fellows. I was hoping to get out for a run with just the motor and do some calculations....but the weather has always been just too good and the winds too inviting to get the sails up and shut the noise maker off.

Tides will not be a problem on this trip, all inland lakes and canal. Kingston to Ottawa on the Rideau Canal. Lots of history to explore, but not much sailing.

http://www.rideau-info.com/canal/map-waterway.html

I will keep tract of fuel and report back.

Don
Living Water

[Vectordirector]

I hear you about noise.  Motoring is not fun.  Outboards are too noisy and diesels are too stinky.  My next motor may be a Torqeedo.  The prices are coming down and battery technology is ever improving.  Plus, I have plenty of sun to charge it.  Solar power may not work so well in Canada, but down here it is perfect. 

That looks to be a beautiful trip.  Have fun and be safe.

Vectordirector

[alsantini]

This is a great discussion.  Let me add a little bit.  When I worked at a boat place part time we used to tell customers to put a decimal point ahead of their HP and that is how much gas you will use at hull speed.  The important thing was not to go beyond what was necessary to achieve hull speed.  Like Vector said, 1/2 throttle gets him to hull speed and anything more just is noise and burns more fuel.  So, a 6 hp should use .6 Gal/Per/hour and if hull speed is 5.6 mph then .6 gets you to 5.6 miles. 1.2 = 11.2 miles 2.4 = 22.4 miles etc.   I calculate hull speed at 5.6 or so.
I have 3 gal onboard in the main tank and carry 1.5 gal in a pony tank.  They both fit with a quart of oil into the Eclipse fuel locker with a small tool box.  My motor has about a quart in the hood that I can pour in should I have difficulty with the tank.  For the sailing I am doing now, I have enough fuel for the summer probably.  I try not to run the tank out.  I have a new tank since the Ethanol ate my pick-up tube forcing me to West Marine.  This tank seems to be able to draw just about all the fuel out of the tank - but I really do not want to find out.  LOL  BTW engine loves pure gas - found that out in Florida over winter.  This Spring I actually drove up to Broadhead Wisconsin to purchase non-ethanol fuel.  Happy motor....

[Craig]

Not exactly a mileage comment but after having fuel problems with the 6 HP Tohatsu on the Suncat I added an in-line fuel filter in the the fuel line from the tank......just to be sure. Brian is mostly correct about diesel "stink". Fortunately the 2 cyl Yanmar on Kailani does not. A pleasant surprise! As a comparison to the Tohatsu, the Yanmar diesel on Kailani burns about 1qt per hour at 5 knots or about 20+ mpg. All that being said, I can't wait to shut the engine down as soon as I can.

[Vectordirector]

Hey Craig,

Lovely weather we're having.  I'm still loving it down here though.  I think I'm a little more sensitive to diesel/jet engine fumes than most people.  I used to walk from the parking garage at ORD to the tower, right past a line of idling busses and trucks, some sitting there spewing for hours.  The exhaust of the planes, buses, trucks, etc.  was to say the least, pungent.  I did this 12 times a week, back and forth for 5 years, until we moved to Elgin.  At times the smoke just hung in the air and you could cut it with a knife.  I'm sure Al knows what I'm talking about.   This was 25 years ago so the "clean" low sulfer diesels didn't exist yet.  It was nauseating to walk past, and if the wind was blowing the wrong way, it would come right into the air handlers for the tower.  We used to joke about "I love the smell of jet fuel in the morning", all the while knowing how bad for us it was to breathe that stuff.  To this day, I can't stand the smell of diesel.  The newer ones are much better though.  I was in London a couple of years ago,  most everything there is diesel.  Didn't notice a bad diesel smell at all.  I haven't been on a newer sailboat with diesel, I'm sure it is much better than it was on the last boat I sailed on with a diesel some 20 years ago.  Glad to hear that you are happy with yours.   The best part of sailing is killing the motor and enjoying the silence.  The worst part is the silence when you can't get the engine started.  There is something to be said about the reliability of a diesel.   They do have thier advantages in the marine environment.

I always look for you when I'm out, haven't seen Kailani out yet.  Do you mostly stay up in the river?  I haven't gotten up past Fishville yet.  With prevailing winds SW, I usually start off upwind (south) so it is an easy sail downwind back to Ponce.  I also don't have a depth finder so I tend to stay out in the harbor where there is plenty of water.  Give me a shout next time you are going sailing,  we can meet out on the water and sail around for a couple of hours.  I'm sure it will stop raining someday! 

Bryan

[Craig]

Hi Brian,
Have not been out for a couple of weeks. Had Kailani out for a bottom job. Was not happy with the bottom paint from factory. Now has Micron 66 ablative which has worked well for me in the past and Practical Sailor rated best in tests conducted in Sarasota which has a similar fouling environment to PG. I am usually in the area between the bridge and Ponce Park. If the weather clears this week I hope to be out later this week.Will look for you on the water and give you a shout if I get out. I do like the confidence that when I turn the key, the motor will start. Have had antibacterial/stabilizer in the tank since day one. I use automotive diesel since I use so little fuel and there is no fuel dock at Laishley.  I hear you re JP smell! On reason we did not buy in PGI was that the first mate was not excited about the sound/smell of neighbors(diesel & gas) firing up across the canal.

[Vectordirector]

I really don't find it an issue to tell the truth.  None of the big sailboats in the canals here seem to go out at all.  Arthur says that many have been sitting so long that they couldn't start 'em if they wanted to.  On my canal there is very little activity in season and even less right now.  To tell the truth, PGI is aging rapidly and most of the residents just couldn't handle a sailboat anymore, and they know it. I don't expect I'll be able to handle something like a Catalina 30 when I'm 80.    I sailed last Tuesday and was the only sailboat out.  The Isles is full of boats that never move, just like most marinas.  It is truly sad.  At some age you have to say, enough, and put the boat up for sale, or just let it sit and deteriorate.  Few people have the desire to buy one of these 30+ year old boats that need big $$$ and time to get back in sailing condition.  So they sit.  Powerboats too.  Big ones, small ones, kayaks, jet skis, hundreds of them. 

Glad you like your diesel.  They seem to have made them much cleaner and quieter.  Wednesday and Thursday looking possible.  We'll see.  We usually head out noonish, If Arthur is with me on Wednesday.  Thursday I'm solo. 

Talk to you later,

Bryan   

[mayrel]

We have the Tohatsu 6hp Pro-Sail with a Mac's prop protector on our CP19.  We have run the motor at about 1/4 throttle and achieved 4.5-5mph. This was heading directly into about a 17mph wind and 3.5' chop. I've kept records on the hours run for break-in purposes.  So far I ran about 8 hours on 2.75 gal of fuel, which seems quite good, although I haven't done the calculations to determine actual mpg.  I did add a fuel demand valve which is suppose to only let fuel flow when the motor is running. I had forgotten to release the pressure in the tank with the hose connected to the motor and had gas seeping.  I also carry a 2 gal and 1 gal reserve just in case.  Hope this helps...John

[waterwheels]

Thanks John

Good information and very helpful. I think I can squeeze a one gallon tank in as a reserve, just for comfort.
I will have to watch the pressure build up issue.

thanks Don
Living Water

[waterwheels]

Well I took the extra gallon can but never needed it at all. Got to the first place with fuel and looked at the gauge and it was still on full. Picked up the can to make sure the gauge wasn't stuck.
Motored for 64 miles before stopping for fuel. It took 2.3 US gallons (9 Litres) to fill it back up. Only used 7.1 gallons or 27 litres to do 184 miles. Spent more on ice cream than fuel.

Got to love small boats.

Don

[alsantini]

Those ice cream bills can kill you.....  or beer bills for that matter!  Guess you did really well in the mileage category.  Get any sailing in or was it all motoring?  Boat looks great too....   One additional question: what fuel were you using? E-10 or pure gas?  I am in the middle of my own study and so far have concluded that my little Nissan 4 hp 4 stroke absolutely loves pure gas and hates E-10.  I am convinced that the mileage is better too.