Standby Fuel Supply

Continious learning in a changing world. Our fuel is not our Father’s fuel..

During the last year, I’ve made the time to tear into two of the Yanmar Clone Fuel tanks just to see what goes on inside. I can’t tell you all of what has been run through the tanks and fuel lines, I was running commercially sold bio diesel in one till the short hose between the tank and the injection pump spilt, the stock hose will last less that a year, and if your fuel isn’t shut off, you’ll find all of it on the ground or your shop floor as I did with my re powered Cushman Truckster.

 When I looked inside the fuel tank, I was alarmed! There was all kinds of crude in the bottom, and gunk clinging to the walls of the tank, the (in the tank filter) was half blocked with what looked like varnish. So what’s the lesson? I think it’s fairly important to have a fuel tank you can easily look inside of, and that you can clean if you have a fuel separation problem, or if it becomes contaminated. This is another reason to consider boat tanks. The plastic is far less reactive than the bare metal we see in some fuel tanks, and there may be less tendency for condensation to form. but what I really like, is you can quickly disconnect the tank, and take it to good light, since the tank wall is translucent, you can see into every corner of the tank through the opening. If you have a filter between this tank with a water trap, and an area where you can visually inspect your fuel, you will have far fewer surprises, and you don’t want to be surprised when you need backup power.

This week, I removed another stock tank from a yanmar clone, and I found a sticky mess in that short stock hose between the tank and injector, the stuff is very dark, but there was also much lighter stuff in the same hose. It easily clings to a paper towel without wicking into the paper fiber.  What would happen if I tried to fire this engine? I won’t know, as I will remove the pump, clean it and inspect it first. but.. we know it easily passed through the stock filter in the tank.

With these personal experiences and others, I would never run bio fuels, home brew fuels in a generator without good filters, a bowl you can see into >AND< and selecter valve and second fuel supply full of petrol diesel that will allow you to purge your injection pump, and the entire high pressure side to the injector intself before shutting down. You may be lucky, and not have problems, but in my experience, everytime we depend on luck, we get burned. Murphy says.. The wife will be there to witness the failure, the kids will be cold, and they’ll all Question the value of your handy work and the money you spent on backup power. The kids will say they could have gone to Disneyland, the Wife will say she could have bought new carpets, and maybe even new drapes..       

We have moderate temperatures here in Western Washington, but  I have seen the temperatures in the single digits, I have also seen diesel fuel sold at the pump cause problems at above freezing temperatures. The point I attempt to make is some of these fuels at NOT yet well understood, but they are on sale at the pump.

We know that the majority of fuel sold in the USA passes through autos and fleet vehicles, their fuel systems are often sealed, and people with newer cars say they even get a warning on the dash WHEN their fuel cap is loose. There may be more than one reason for this, we know fuel vapors can escape, but we also know that when the tank and fuel cool, we form a vacuum that can suck in moist air, and this will condense on the walls of the tank and contaminate our fuel.

With this said. The majority of those who buy fuel could be satisified with the performance WHEN it does really bad things to your small engine, you are the minority, you are a one percenter, and your concerns will seldom get attention. Part of the answer will be to build a better fuel system, and I think metal is the wrong stuff. I remember all the problems the Washington State Ferry had when they decided to burn biofuels, expecially at the landings. They couldn’t change filters fast enough, and I’m sure you can find a paper on their findings. We have a Washington State Ferry System Engineer in our DIYer Group, I’m wondering if he has a link to their study?

As a last thought, this Yanmar clone tank has a most beautiful powder coated exterior, or at least that’s what I think it is, but the inside looks no better than a primer. I’m wondering if bare metal inside reacts with the fuel? We know it would react with any moisture in there, and I know the stock system won’t keep the moisture out. Got a vent on that standby Generator tank? Keep in closed..

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4 Responses to Standby Fuel Supply

  1. George B. says:

    Note: comment on stock fuel line break down was caused by bio-fuel, now that I think about it, this fuel may have reacted with a paint on the inside of the tank that was totally compatible with petrol fuels! Who knows wihtout more testing, too bad they didn’t powdercoat the inside.

  2. Tracy says:

    My homebrew biodiesel forms a varnish “skin” on it over time. This is caused by oxidation. Biodiesel is not a good storage fuel, and really should be used as soon as possible. If I were going to try to store biodiesel, I would put it in a light-impervious container that is full except for a small expansion area, and sealed airtight.

    • George B. says:

      Good comment Tracy, I’ll continue to put mine in a translucent container inside a shed or cover that excludes all light, I want t be able to see inside the tank. Some of us have fuel systems with a loop that effectively ‘polishes’ the fuel. This migh help remove that varnish

  3. Ned Funnell says:

    A product exists for lining the inside of fuel tanks called ‘POR-15’. It’s a common solution to rust inside of fuel tanks for motorcycles and cars which are being restored. It’s supposed to be impervious to all kinds of fuel, and I’ve heard only good things about it. I bought a little can to do the inside of my motorcycle’s tank with- we’ll see how it goes.

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