Building a Cheap Extended Run Tank for my Kipor/McCulloch Inverter Generator

One of the most interesting things about my solar powered office is that the entire office is a machine, it’s a very obvious machine, and I don’t have an instruction manual for operation.  It’s something I’m learning as I go - and last winter involved an awful lot of learning.

This is a companion discussion topic for the original entry at

(Comments from Blogger)

2017-12-17 by Daniel

Non-ferrous fuel pickup weights mandatory!

One can find lead-free fishing weight, lead-free auto wheel balance ribbon or even coil some lead-free solid core plumbers solder around the pickup filter stem… If there is enough used items around the Homesteads then brass plumbing parts or washers might be available just for looking…

Those flash (extremely thin plating to protect product in storage prior to sale) galvanized washers inside the steel can is bad mojo, never both sides/pieces in percussive pair of iron/steel objects around flammable vapors!

2017-12-17 by Russell Graves

Hm, that’s a valid point - I hadn’t really thought about that. I think the washers are zinc all the way through, but I don’t know for sure. I may replace those with lead weights.

2017-12-17 by Daniel

They used to use an 80/20 lead-zinc alloy as a dipped coating on sheet steel gasoline tanks, zinc is the key as if/when dissimilar metal leaching or exchange happens its only the zinc that suffers (on very long term basis) thus its sacrificial, and benefits ferrous metal - imagine the fuel pickup protecting the steel gas can… so maybe just go with zinc, thats all the ‘lead-free’ stuffs I mentioned above are… win/win situation :slight_smile:

2017-12-18 by Daniel

eeek! Skip solder suggestion, no zinc there. I’m back to the salt mine, move along… :slight_smile:

2017-12-25 by dthompson4447

Inside the gas can is FAR too rich to burn, never
when storing, leave a little gas, the fumes discourage the leaf-cutter bees

2017-12-25 by An old fart engineer

If you put the me of now in your situation I would have converted the generator to run on propane. You already have it available. The conversion parts aren’t cheap, I know, but a whole bunch of problems around gasoline just go away. Also the expensive parts for the conversion (mainly the regulator) will most likely outlast any particular generator.

2017-12-25 by Russell Graves

I was planning on it, and then realized that the conversion kit cost as much as my generator. Plus, I’d need a lot more propane out there - my 7 gallons gets me through the winter thermally, but I’d need a much bigger tank out there to run a generator all winter.

However, I have access to a fairly large tank for the asking, if I want it - it’d need to be recertified (likely), and would need a vapor outlet added to the tank (it only has a liquid outlet, and I’d want to run my heater from it too). If I put that out there, then, yes, a propane conversion kit makes a ton of sense.

2019-12-12 by Unknown

You can also buy 2" PVC caps that are flat on the top with no recess to fill with hot glue. Thanks the tutorial on this. It will help me modify a newer plastic can.

2020-09-02 by Best Dad Ever!!

Can’t you just use a boat motor tank? It already has a filter and lines?

2020-09-06 by Russell Graves

Probably. But I didn’t have any of those laying around.

2020-11-16 by Tommy B

We have a craftsman 2200i for the nights on a city camp… and it doesn’t do the night on a full fuel tank. I call that a stupid design… but yeah I think ours also use a vacuum pump as the plug has a vent valve on it. I might try to add a secondary tank aside.

2020-12-18 by Harry k

Fantastic job with the illustrations ! I just bought a Generac 7127 IQ 3500 and the fuel tank is on top, so I do not think there is a fuel pump. But not sure either & cannot seem to find this answer. Anyway, I wanted to ask your thoughts on a extended run tank system for this generator. My immediate thought is a high tank & siphon. But not sure how safe that would be. Or a pressurized aux. fuel tank. Your thoughts on how to do this would be appreciated.

2020-12-18 by Russell Graves

I wouldn’t use a pressurized anything for that sort of fuel system.

If the tank is sealed outside the cap, just put a sealed cap on with a gravity drain from a higher tank. It should work fine.

Continuing the discussion from Building a Cheap Extended Run Tank for my Kipor/McCulloch Inverter Generator:

I tried the gravity feed with a 2 gallon fuel can higher than my generator, Genmax 3200i which does not have a fuel pump. The gravity feed flooded the carburetor and fuel poured from the overflow. I tried it with fuel can sitting on the ground to no avail. The fuel cap on the generator is sealed tight. The pickup hose is close to the bottom of the 2 gallon extended fuel can. Hope someone can help me fugure out how to make thus work. Thanks

If it doesn’t have a fuel pump, the system I use won’t work - it relies on sucking the fuel up and over. I’m somewhat surprised that your carburetor can’t handle a bit more fuel pressure - if the float is working properly, the needle valve should be able to seal a decent head, at least in terms of extra fuel tank capacity. You might check the condition of your needle valve and see if it’s worn or has damage on the seat, but that would impact even just the internal tank.

Needless to say I’m very frustrated over what I thought was going to be so simple, haha… I guess I’m stuck with one gallon (on board) tank. The generator is new so not sure aboutvthe needle value being an issue, like you said it would affect the on board tank as well. I’ve only done the break-in run, changed the oil and run one tank through it. There must be someway to make this work. Anyway, thanks for your quick reply.

You’re sure the cap and tank are entirely sealed, not vented somewhere?

If so, I’d expect having your aux tank set at roughly the same level, or only slightly higher, would work. It should siphon over as the sealed tank level drops, but I don’t know how much actual suction one gets off that. Mine certainly relies on the fuel pump to pull a vacuum. It’s worth trying to see what it does.

Another option, and I’m not sure if such a device exists, would be to have a small float valve on your aux tank. Put the aux tank higher, and have a float valve on the end of the transfer line such that it only feeds in if the main tank level has dropped. This would let you keep the main tank on the generator full, without adding the head pressure of the extra tank.

I don’t think there’s an air leak i threaded the brass connector in the extra gas cap like you did. I also added an in-line shut-off value just above generator fuel cap. Then i throttled the fuel flow down but it still dumped fuel through the overflow. I also put an in-line check value (backflow preventer) just below the fuel cap inside the on-board fuel tank. Didn’t work. Guess I’ll sell this generator and buy one that has a FUEL PUMP and be done with the frustration. Anyway thanks for your help and appreciate your website.