# Adding auxillary fuel tank to generator



## whistler (Apr 20, 2005)

I have an off-grid cabin where electricity is supplied solely by generator power. Eventually I would like to move to solar power -- that's not in the cards for a while though.

I have two generators, a Honda EU2000 and a Generac 8500 watt, inside a smallish shed with power vents. I hate having the fill the darn things on a regular basis because a) I always manage to spill gas, and b) the shed is difficult to work in due to size and configuration. Moreover, it kind of stinks when the generator runs out of gas about 20 minutes before you are ready to shut it down for the night.

So, I would like to mount a large tank (15-30 gallon) outside the shed with feeds to the two generators. This auxillary tank would sit about 24" max above the height of the existing tanks. In a gravity feed situation would this create too much pressure going into the carb?

Also, the Generac has an external quick disconnect on the existing fuel line to facilitate removing the 6 gallon tank. I can't think of a reason why I couldn't just put a compatible quick connect on the line from the auxillary tank. Or am I missing something?

Last question. I don't want to take apart the Honda in order to access the fuel line. I do like the portability aspect even though 95% of its run time is in the shed. Would it be possible to buy an extra gas cap and convert it such that it could connect to the line from the auxillary tank?

Obviously the auxillary tank would be vented.

It seems like this should all work, but I am not a small engine (or large engine, for that matter) kind of guy. So any thoughts or comments would be much appreciated.

Thanks.

Whistler


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## Cotton Picker (Oct 10, 2008)

Hi Whistler....

I have an idea to run past you...... It would allow you the best of both worlds.... Auxiliary fuel capacity without compromising portability......

You will need to procure a non-vented fuel cap for the Genny...... Pipe thread on the end that affixes to the fuel cap... And the other end should accept a fuel line..... You then drill a small hole in the top of the fuel cap and insert a small brass elbow.... You could make a backup washer of sorts by using a female pipe nipple on the inside of the fuel cap to lend some stability and strength to the apparatus.... Extra, flat washers will further strengthen the integrity of the fuel cap.... Just make sure that the OD of the washers does not compromise the ability to screw the fuel cap on tightly to the Genny's fuel tank..... 

Brass ElbowExample...

http://www.google.com/imgres?imgurl...T&sa=X&oi=image_result&resnum=3&ct=image&cd=1

Run a fuel line from the auxiliary tank to the Genny....... The action of the Genny consuming the fuel will then draw the fuel from the VENTED auxiliary tank directly into the Genny's fuel tank...... Make sure that the Genny is full of fuel beforehand or the system won't work properly... Due to the fact that air compresses and fuel doesn't..... If there is an air pocket in the Genny's tank... It won't draw the fuel from the reserve tank effectively.

With this type of setup, you shouldn't require a gravity assist for fuel flow.... As you are in effect drawing the fuel to the Genny by vacuum.


Hope this helps...


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## frank (Dec 16, 2008)

Some generators have easy access to the fuel line that feeds the carb. It's simply a matter of squeezing the compressable clip, and replacing the fuel line with a similar sized line from an aux. fuel tank. Leave the existing fuel tank in place, and switch back over if you need portability.


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## wy_white_wolf (Oct 14, 2004)

They do make extended run tanks for the honda. Might check into how they hook up.

http://www.wisesales.com/HondaAccessories_New.html


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## Michael Kawalek (Jun 21, 2007)

Our well generator has a system somewhat like what you are describing. The generator sits inside our wellhouse, while the fuel tank is outside. The fuel flow is not by gravity, but by suction as Cotton picker described above, with a fuel hose running through the wall of the wellhouse to the outside tank.

The fuel system however has a 12 volt priming pump that you must run for a few seconds (15-30 usually) to pull fuel out of the tank to the carburator. You can hear the sound of pumping change as the fuel is pullled out of the tank and finally fills the bowl. Once you have primed the system, you press the start button, and crank the generator over until it starts. Once started, the generator itself continues to pull fuel from the tank by suction untill it's empty.
Michael


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## rambler (Jan 20, 2004)

I'm no expert.

I think you could do the disconnect genny as you say - uncouple the regular tank & couple up the outside tank.

I'd not at all want to run gravity feed into the tank of the small genny. Any leak at all & you are flooding the floor of your small building with 10+ gallons of gasoline.... Fuel tanks are designed to vent, not seal up tight, and making that top cap totally perfect is not easy. This is just a problem waiting to happen.

If something fails, you want the thing to stop, not flood gasoline all over. Better to run out of fuel, than spray it all over.

The syphon system as others mention is good, or connecting directly to the carb, bypassing the gas tank is doable.

--->Paul


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## Gary in ohio (May 11, 2002)

Whatever you do it safely. Dont use portable cans for your tank. use only fuel grade hoses.


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## Cotton Picker (Oct 10, 2008)

rambler said:


> I'd not at all want to run gravity feed into the tank of the small genny. Any leak at all & you are flooding the floor of your small building with 10+ gallons of gasoline.... Fuel tanks are designed to vent, not seal up tight, and making that top cap totally perfect is not easy. This is just a problem waiting to happen.
> 
> If something fails, you want the thing to stop, not flood gasoline all over. Better to run out of fuel, than spray it all over.
> 
> ...


Paul....

I agree that a gravity feed fuel delivery, is an accident waiting to happen...

With a siphon type delivery system... If the system gets compromised... There is less chance of a major fuel spill occuring....

A safety measure could also be applied with that siphon system... In that if you used a rigid PVC conduit to encase that delivery fuel line..... You would not only relieve the weight strain at the junction... You could also install a catch basin to absorb potential spills......

Ne vous fÃ¢chez pas, s'il vous plait... Just my $.02


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## artificer (Feb 26, 2007)

http://blog.rv.net/2008/09/extended-run-time-generator-fuel-tank/

http://www.braingarage.com/Dons/Travels/articles/generators/fuel tank.html

http://pittsburgh.craigslist.org/for/1053918231.html

Michael


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## whistler (Apr 20, 2005)

Wow! Thanks for all the help guys! I checked out the links provided and am quite intrigued.

While it should have been obvious, I didn't even think about the spillage problem. 

Thanks again.

Whistler


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## fordy (Sep 13, 2003)

............I would simply advise you too , NOT , leave those gensets in that storage shed , while you're gone ! Sooner or later someone will assume ownership of them in you're absence . , fordy


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