Extending Your Honda Generator Run Time

Outside of raising an antenna tower, probably the most dangerous activity during Field Day is refueling the generator.   A few clubs have back-up generators that they can quickly switch over.  Other clubs have battery backup that allows the rigs to continue to operate during refueling.  Some clubs simply kill power and wait for the generator to cool down enough to safely refuel.  However there are those clubs that decide to refuel while the generator is running — something that is VERY dangerous.

Many clubs use small Honda inverter generators, like the EU-2000i, because they are VERY quiet and are fuel efficient.  Their inverter output produces much cleaner output power too.  A generator like the EU-2000i will produce full output for about four hours before needing to be refueled.  But there is an easy way to extend that run time to over 28 hours — more than enough for the entire Field Day event — by using an extended run fuel system.

You can find assembled extended run fuel systems online by Googling “Honda Extended Run Gas Tank”.  You can even order them through Amazon.com by searching for the same thing.  The entire system tends to be pretty expensive, running about $180. All the parts except the Custom Extended Run Fuel Cap can be purchased cheaper locally, and if you are a boater, you probably have everything you need except for the cap and one gas fitting.  Four items are required:

1) Honda Extended Run Fuel Cap:  This is the only uncommon part.  Many vendors sell these on eBay and Amazon.  Expect to pay about $35 with shipping.

Extended Run Gas Cap

2) Marine Gas Fitting:  These are brass fittings designed to mate with the 1/4″ opening on the fuel cap or marine gas tank.  If you have a boat, pick a fitting that matches your existing fuel line/tank.  They sell for about $4 at Walmart.

Marine Gas Fitting

3) Marine Fuel Line:  This is the hose that connects your Marine Gas Tank to the Extended Run Gas Cap.  Its couplings should match the Marine Fuel Fittings you are using (like Johnson/Evinrude).  Expect to pay $20 to $30.

Marine Fuel Line

4) Marine Fuel Tank:  Expect to pay $25 to $50 for a new 6-galon fuel tank.  They generally don’t come with the fuel fittings, so be sure to buy one that matches your fuel line and Extended Run Gas Cap fittings.

Marine Gas Tank

Using the Extended Run System:

1. Fill the generator gas tank to near the top
2. Cap the generator gas tank with the Extended Run Cap, rather than the usual Honda supplied Cap
3. Fill your marine fuel tank
4. Attach the fuel line to the marine fuel tank.  Press the primer bulb several times to fill the fuel line and bulb.
5. Open the vent on the marine fuel tank
6. Place the marine fuel tank as far from the generator as your fuel line will allow, level with the generator
7. Attach the fuel line to the Extended Run Cap
8. Start the generator and enjoy 28+ hours of run time without refueling

The system works by vacuum, drawing fuel from the marine tank into the Honda tank as fuel is consumed by the generator.  So it isn’t gravity fed.  On the other hand, I doubt that the generator would draw fuel up hill — so keep the tank and generator on the same level.  I used such as system following storm damage in 2011 which allowed me to refuel every other day during daylight hours, as my power demand was low.  Just remember to follow the manufacturer’s recommendation for oil changes — its easy to rack up a lot of hours when running with such a system.