External tanks for generators: how to connect via the cap? Suction? Gravity? (1 Viewer)

[e9999]

yes, been playing with a new toy...


curious about something:

if you connect an external tank to a generator through the cap, how does that work best?

I've seen those caps sold for the Honda EU gens. Just a cap with a hole. But how would you rig that? Does the tank undergo sufficient enough suction that it could suck fuel from an external tank with a pickup? (There must be some suction since it seems like if you keep the cap closed when running it the gen will eventually stop.)

Or could you use gravity feed? But then would that not fill up completely the tank, which is probably not a great idea?


Anybody tried to modify a regular EU cap for this?



added: oh man, saw a nifty attachment that allows you to use LP to run the generator too...

 

[e9999]

anybody?

with finding a fitting cap and rigging a pass through it could be a very inexpensive DIY project vs the sold version.



added: well, from what I've read it seems like the fuel pump is strong enough to suck fuel from an auxiliary tank without any need for gravity assist. Seems like most people just rig the simplest setup: a tapped cap, a bulb fuel line, and an aux boat fuel container on the ground. Seems to work as is without the need for fine tuning, interestingly. (Not clear whether the tank in the generator ends up being full all the time or not.)
You need a cap though: beautiful aluminum ones pretapped for about $30+ on ebay or about $20 (?) for the OEM which can be modified. Or use your existing one but that's kind of a one way street I think. Or of course be lucky and scavenge one that will fit in the grand DIY tradition...

 

[greentruck]

I'd think that it would rely on siphon action. There wouldn't be any suction pressure in the tank itself. So placement of the aux can and priming the line to the cap will be the key to this working.

On the other hand, sounds like a worrisome mod. How long does the genny run on a tankful? Do you really need the continuous run capability enough to put up with the hassle?

 

[e9999]

I'd think that it would rely on siphon action. There wouldn't be any suction pressure in the tank itself. So placement of the aux can and priming the line to the cap will be the key to this working.

On the other hand, sounds like a worrisome mod. How long does the genny run on a tankful? Do you really need the continuous run capability enough to put up with the hassle?

about siphon: not obvious. The boat cans are typically lower than the generator cap I think and the hose goes just to the gen cap, not all the way down into the gen tank from what I read.

The 2000 will run for about 9hrs at 1/4 load, so if you pull hard on it, it would not last overnight. The 1000 is less I think.

 

[countryboy69]

I just added a fitting to the top of the Honda eu gas cap and ran a 1/4" line into the vent side of a gas can. Works great. No need to fill up the generator everyday. Almost ran for a week. It will siphon the fuel all by itself.

 

[hkeller]

Honda gensets have a fuel pump that creates enough pressure to suck fuel from the external tank. Most others do not have a pump, so the external tanks only work with the Hondas. I've got a Yamaha, without the pump and the external tank does not work with mine. I've heard Honda recommends against the use of the external tank, but I have not confirmed.

 

[Elbert]

why not rig up something like outboard motors use..... use an outboard motor 5 gal tank, and the hose with the pressure bulb and then adapt the end to the cap or modify a cap? Seems like a good idea?