Ok to Use Biodiesel in My Kubota?

Jars of biodiesel labled according to their various sources.

Jars of biodiesel labled according to their various sources.

Biodiesel. This is a topic that gets kicked around quite a bit these days as public awareness of this alternative fuel source increases. This article will focus on whether as a Kubota owner with equipment under warranty, is biodiesel okay to use without damaging your engine or voiding your warranty. This type of fuel is getting popular so if you have not had a look already, it might still be a good idea to familiarize yourself with biodiesel and its properties.

Ok to use? Yes and No
Yes, since late 2006, Kubota has approved certain models of their lineup for running on biodiesel. The catch is the fuel must come from a refiner that is an accredited producer and the fuel must be a B5 blend of 5% bio-fuel and 95% petroleum diesel. So, certain models are not covered and using a fuel blend higher than 5% or fuel that you make in yourself in the back shed are a no-nos.

Right now, some of the models Kubota has approved for B5 blend include:

  • BX1500, BX1800, BX2200, BX1830, BX2230, BX1850, BX2350, BX22, BX23 and BX24
  • B7410, B7510, B7610, B7800, B2630, B3030, B21 and B26
  • L2800, L3400 and L4400 (Kubota’s Super Three engines)
  • L3130, L3430, L3830, L4330, L4630 and L5030
  • L39 and L48 – possibly L45 when it comes out this spring/summer

You can read Kubota’s press release regarding its stance on the use of biodiesel in its equipment and see the full list of models.

Why not Higher Blends?
There is another blend of biodiesel that is trying to make headway – B20 which is a 20/80 blend of bio-fuel and the usual petroleum diesel. In 2003 the Engine Manufacturers Association (EMA) released a ruling that the maximum biodiesel blend for mass-produced agriculture and automotive engines should be B5, not B20. It looks like Kubota is also falling into alignment with this recommendation.

Reading through Kubota’s press release on biodiesel they use a lot of the same terms quoted as the EMA’s for their reasoning behind the use of B5 so it is unclear if Kubota performed their own first-hand testing with biodiesel or is simply following this recommendation.

Drawbacks of Higher Blend Biodiesel
Reading through the EMA’s ruling, they list these reasons against blends higher than 5%:

neat biodiesel and higher percentage biodiesel blends can cause a variety of engine performance problems including filter plugging, injector coking, piston ring sticking and breaking, elastomer seal swelling and hardening/cracking, and severe engine lubricant degradation. In addition, elastomer compatibility with biodiesel remains unclear; therefore, when biodiesel fuels are used, the condition of seals, hoses, gaskets and wire coatings should be monitored regularly.”

“Neat” as in how you have your drink – 100% pure – like without diluting your single malt scotch and ruining the whole thing!

What this means is that if you do decide to go with biodiesel, keep lots of filters on hand for the fuel system or consider installing a secondary fuel filter. Also, biodiesel does not store well for long periods as regular diesel fuel does. It absorbs moisture from the air and lacks the additives to prevent clouding and gelling of the fuel in cold climates. The use of a magnetic block heater would be advised to keep the bio-fuel warm in the tank if your Kubota is spending time in a sub-zero working environment.

Service Department Vic

1 Comment

  1. Victoria Said,

    January 20, 2010 @ 11:18 pm

    Greetings. I have been running my BX1850 on B99 since I bought it almost 3 years ago (been running my cars on it since 2003). Runs great and smells even better. However, late last fall it started lugging a bit when I used the mower. I picked up a pair of new fuel filters, but when I opened it up, discovered that the original fuel lines had turned to telltale molten goo. I was honestly surprised that Kubota would supply their tractors with what I assume must be natural rubber fuel lines on diesels. (Those of us who use biodiesel know that it eats rubber for lunch!) Anyway, I am now in the process of replacing the lines with some of far better quality. I am looking forward to getting my BX back on the road… err, I mean grass again. Love the tractor and love biodiesel. Cheers.

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