# Extended run Fuel tank



## jhicks (Aug 29, 2019)

Ive got an older MAXA generator with a 1 or 2 gal fuel tnak (not 100% sure which). Its gravity feed.

Ive been looking at installing and auxiliary fuel tank so I dont have to keep fueling every 2 hrs. Here in south louisiana we typically can get power outages for a days. 

This gen was givin to me from my grandfather. Its a 4k watt. Plenty for what I need when it comes to necessitates. 

Ive googled for the last few days, and I cannot verify which type of fitting I can use thats fuel resistant. Ive seen some bulkhead fittings, but yet again, Im not sure.

I plan to use at least a 6 gal marine tank and mount it above my gen. And its got to be a gravity feed set up. 

Any help would be appreciated. Thanks.


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## RedOctobyr (Aug 8, 2018)

What kind of fittings? What are you connecting to, exactly? Are you drilling through 2 tanks? Are you able to simply connect to a fuel line going between the original tank and the carb?

I added an external tank to my generator. I drilled through an OEM gas cap, cut NPT threads in it, and used JB Weld to attach a brass tube fitting to the gas cap. The epoxy was to help seal the NPT threads, as I did not want to really tighten the fitting into the plastic cap. The stress would likely crack the cap.

I used a marine tank as the supply, with a fuel-rated dripless quick-connect to join the fuel lines (gas cap to tank). I can find the part number of the fitting I used, if needed. I got it in Walmart's marine section.


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## tabora (Sep 6, 2018)

Something like this in the fuel line in place of the existing fuel shutoff (if any) should do it...

https://www.aircraftspruce.com/cata...z7sdma18-qpd7QU-OKN6xRr_1DzC_UnwaAhmtEALw_wcB

Is it a green Coleman Powermate PM0524000.01 MaxA 4000? If so, it looks like the fuel line is well exposed below the tank.


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## jhicks (Aug 29, 2019)

RedOctobyr said:


> What kind of fittings? What are you connecting to, exactly? Are you drilling through 2 tanks? Are you able to simply connect to a fuel line going between the original tank and the carb?
> 
> I added an external tank to my generator. I drilled through an OEM gas cap, cut NPT threads in it, and used JB Weld to attach a brass tube fitting to the gas cap. The epoxy was to help seal the NPT threads, as I did not want to really tighten the fitting into the plastic cap. The stress would likely crack the cap.
> 
> I used a marine tank as the supply, with a fuel-rated dripless quick-connect to join the fuel lines (gas cap to tank). I can find the part number of the fitting I used, if needed. I got it in Walmart's marine section.


Im need something to put into the marine fuel tank that will seal. I wish my gen had a vacuum feed, but its all gravity. So ill have to mount my tank above my Gen. I found a youtube video, but the guy wasnt specific on what he used.


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## tabora (Sep 6, 2018)

jhicks said:


> Im need something to put into the marine fuel tank that will seal. I wish my gen had a vacuum feed, but its all gravity. So ill have to mount my tank above my Gen. I found a youtube video, but the guy wasnt specific on what he used.


As long as you mount the marine tank above the generator with a standard primer bulb to get the flow started, it will supply the generator just fine from the stock tank top fitting via siphon and will suck the tank almost dry. I ran my Coleman PM1500 this way for MANY years. Just connect into the genset fuel line below the onboard tank with a tank selector valve as suggested above.


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## RedOctobyr (Aug 8, 2018)

(Edit- sorry, tabora and I were replying at the same time) 



Mine (Honda) has a fuel pump, so it will create *some* vacuum, to help pull from the external tank. 

But I've read that you can use an external tank with a Yamaha, which is also gravity fed. As I recall, you need an airtight seal in the generator's tank, but it can be done. If your marine tank is like mine, the purge bulb on the gas line may allow you to draw/pump gas out of the external tank, despite the line coming out the top of the tank. 

I don't remember if those people used a fuel outlet from the bottom of their external tanks. I would be somewhat leery of trying to do that, myself, without being certain that the materials in the bulkhead fittings are gas-safe. 

You probably need to start with the gen's tank almost full (I've had better luck starting that way, even with a fuel pump), and have the external tank positioned above the generator. I'm assuming you're thinking about modifying the cap to accept the external tank's line. Based on that, I'd loosen the generator's cap use the purge bulb to fill the fuel line, and get it flowing into the generator's tank (maybe almost overflowing the tank?), then quickly tighten the generator's cap. 

Do you have a fuel line between your tank and the carb? If so, perhaps you could just buy a different, larger gas tank (universal, etc, or any tank like from a broken lawn tractor), then mount it above the generator, plumbed to the carb? Maybe with a 3-way valve to allow switching between the external and internal tanks.


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## jhicks (Aug 29, 2019)

RedOctobyr said:


> (Edit- sorry, tabora and I were replying at the same time)
> 
> 
> 
> ...




I was going to bypass the original tank completely and use just the aux tank. I was going to make brackets to mount it above my gen.

I seriously dont know a whole lot about Gens. This is the first one ive ever had in my possession. Thats why im trying to make sure i find a bulkhead fitting that fuel safe, ill even use silicone with it as a precaution.


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## jhicks (Aug 29, 2019)

This is my gen (not my pic, found it online, so its a dofferent frame)

If it helps at all.


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## jhicks (Aug 29, 2019)

Not sure if Links are allowed here, but im going to post it anyway.

I assume this would work perfect. And 7 gal is plenty. Id just have to make mounting brackets.


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## RedOctobyr (Aug 8, 2018)

jhicks said:


> I was going to bypass the original tank completely and use just the aux tank. I was going to make brackets to mount it above my gen.
> 
> I seriously dont know a whole lot about Gens. This is the first one ive ever had in my possession. Thats why im trying to make sure i find a bulkhead fitting that fuel safe, ill even use silicone with it as a precaution.


Check materials-compatibility carefully. Silicone is not safe to use with gasoline, from what I've read. Take a look here, for instance: 

https://www.permatex.com/faqwd/can-use-permatex-ultra-blue-rtv-seal-gas-gauge-sending-unit-gas-tank/

JB Weld is apparently safe to use with gas, once it's dried. I used it sort of like Teflon tape, to help seal the NPT threads I added to my modified plastic gas cap. Certain o-ring materials are safe with gas, but not all. 

Given that you can use the line that's currently coming from the stock tank, that should help simplify things. You don't need to worry about as much, except for how to safely get gas out of the bottom of the external tank. And if that turned into a real mess (positioning/tightening a bulkhead fitting inside the tank may be difficult, since you can only reach in through the fill hole), you could probably just use something that's intended as a fuel tank, since it will already have an outlet at the bottom.

(Oops, sorry, somehow I hadn't seen your next post about the tank you found. That might work nicely.)


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## tabora (Sep 6, 2018)

jhicks said:


> Not sure if Links are allowed here, but im going to post it anyway.
> 
> I assume this would work perfect. And 7 gal is plenty. Id just have to make mounting brackets.
> 
> https://www.amazon.com/Samger-Gallo...t=&hvlocphy=1017996&hvtargid=pla-797575631913


 That is the tank I used to replace the marine tank on my Onan 2.8. Works great, so far... Here's a picture:
https://www.powerequipmentforum.com/forum/66358-post14.html


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## jhicks (Aug 29, 2019)

RedOctobyr said:


> Check materials-compatibility carefully. Silicone is not safe to use with gasoline, from what I've read. Take a look here, for instance:
> 
> https://www.permatex.com/faqwd/can-use-permatex-ultra-blue-rtv-seal-gas-gauge-sending-unit-gas-tank/
> 
> ...




Im hoping its as simple as buying that tank ha ha. thanks.


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