Honda GX340-390 external gas tank

Machine Repairs
1

I would like to know if anyone knows how to properly set up external gas tank to be able to run longer hours (looking at getting a 9 or 12 gallon tank) on a honda gx 340-390. Any help would be appreciated. Here is a link of what im looking at.

Any help very much appreciated.

2

They don’t have a fuel pump so 4 options:

  1. Mount larger tank above machine to gravity feed and wait for the fireball or the carb float to flood out from the head pressure.

  2. NEW FUEL PUMP REPLACES ONAN 149-2331-03 149-2331 For ONAN GENERATOR 3.5-5.5 PSI 686494064065 | eBay
    Add a battery and hope pressure isn’t to high

  3. Get a commercial grade engine

  4. Live with having to refuel every hour.

3 Likes
3

I agree…and, ironically, these units are advertised as commercial machines.

4

If it’s going to run all day it needs more fuel capacity, more oil capacity and an external oil filter

1 Like
5

Just add a fuel pump.

6

I thought about this too… I was going to buy a 15 gallon rectangular plastic gas tank with a filler neck, get the local welder to weld a frame over my machine, and use it and gravity fill my 390 when it came time to refill the tank. I’m not an engineer so I wasn’t planning on hooking it up to the gas tank. Just fill it so I could stop fussing with gas cans…

And then I decided that’s a heck of a lot a work and money to avoid filling the tank from regular old gas can. Next year I’m buying a larger, belt drive machine anyway. Large fuel capacity is on my wish list right there with electric start.

1 Like
7

You could have a fill/transfer system like in this rig:

8

they did a great job on this rig looks awesome!

9

That is a huge liability the vendor and customer is taking. What happens when you don’t stop the fuel transfer in time? You can see in the the top. Little over flow and you have gas running onto the engine.

1 Like
10

I wondered about that as well. Here’s Kevin’s reply to a comment on the video:

IMG_6171.PNG640×1136 334 KB

So any overflow will just go back to the auxiliary tank.

11

I spent days looking for a good way to do this since my fuel tank has 2 pickups but after a lot of research, even the guys that got it to work using after market pumps, etc. no one was particularly happy with the results and reliability. And since I don’t plan on keeping it forever and rarely use just gave up on it.