Bio-Diesel fuel breakdown.

[Andrew Mackey]

Has any one encountered a Bio-Diesel fuel storage problem? I was recently told I had to remove and purge the fuel system in my local engine club's Lister diesel generater, due to the fact that the Bio-Diesel fuel we were using was going rancid in the fuel tank! The factory fuel tank was full to the top (approximately 6 gallons). One of our members was checking our building, when he noticed that the Bio-Diesel fuel we had in some clear storage containers had changed color. When opened, the fuel smelled heavily rancid, and the fuel itself did not seem to flow as easily as when we got it new. Instead of being a pale yellow color, it was now a deep brown, and instead of being near odorless, it smelled awful. The Bio-Diesel was about 5 months old.

I drained out the fuel tank, filled it with fresh regular diesel, and opened the drain on the fuel reservoir/filter on the engine itself. The old Bio fuel flowed slowly, but was finally purged out of the assembly after about 15 minutes. I then tried to start the Lister, without cleaning out the injecter. It took 4 tries to finally get the engine to fire up. It started slowly, without much power, and smoked white plumes of smoke for a while, until the engine got up to speed. It knocked quite a bit more than usual as well. Once up to speed, it reacted slowly to load, and didn't seel to have enough power to maintain speed, when loaded up. After about 10 minutes, performance improved, as the new fuel got thru the system. In about an hour's time, the engine was behaving itself just fine. A re-start tne next day, gave no issues as well, the start was on the first compression stroke, and the engine quickly came up to speed. Load was accepted and held immediatly, so I think all the old fuel has been purged out by the new fuel.

Has anyone else had issues with Bio Diesel fuels?
Andrew

[Mikey4026]

Yep!! It does not store well. Not very well suited for something that does not run everyday and allows the fuel to go unused. It also does not work well in cold weather. It jells up much worse than diesel fuel.
In warm weather and continous use, it seems to work well.
It sure smells nasty when it goes rancid.
Mikey

[Mikey4026]

PS: You might want to change that fuel filter. Biodiesel will loosen any bit of anything in the fuel system and get it into the filters. (Rust, sediment, water, zinc, dirt, paint, bugs, lizards, birds, snakes, bees nests).
Mikey

[Larry Rusch]

Rancidity is typically indicative of bacterial contamination. This can occur in a variety of ways. Poor quality control during manufacture or sloppy handling/storage after the fact are likely suspects. Your biodiesel source may not be doing the chemistry right, a lot of backyard operations cut corners by not removing the free fatty acids properly prior to transesterification or not doing a clean separation of the aqueous layer after. Incomplete transesterification is also a possibility. If the raw oil is particularly icky all of these factors become increasingly important.
A second, although less likely source of trouble is contamination by oxidation catalysts. Metallic oxides (rust) are the usual culprits, but oxidation is evidenced more by gum formation, and a corresponding increase in viscosity, than by rancidity. This is usually a factor when the source oil has a greater percentage of highly unsaturated fatty acid components. Biodiesel made from vegetable oils are more prone to this than those made from animal fats as animal fat (except for the fish oils) is completely saturated.
Properly made and stored biodiesel has an indefinite shelf life in principle, and should last at least a year under normal/routine circumstances. It should not be exposed to high temperatures or sunlight.
Hope this helps.

[RickMinn]

even the best diesel in warm climates starts growing bacteria, yeasts, fugus and other bad stuff that will clog fuel lines and may destroy a good engine if its fluid enogth to fire the engine yet let it run very rough. this is a common problem of deisel engine boats in the carribean when the boats sit for months. there are additives and adding more then what u need is sometimes worse then adding any at all. i agree that wast oil can be safley run on many diesel engines but to store it to long even with additives is asking for trouble. i may be all wet but thats my 2 gallons woth.

[ehpower2]

i only run engines that i own with gas that is less than 15 days old be it diesel or gas and i always drain my tanks on my engines to so not to wreck anything or make me have to clean anything out.

[paxman merv]

i know that this could be taken as slightly off topic but i will put it here anyhow.
The biodiesel users might find it of interest to know that biodiesel when used in modern common rail systems seems to, here in the UK any way, wreck the neoprene seals in the entire fuel system. Be warned when using biodiesel in new CDI vehicles. Its fine for the old block pump systems though.

[SDP]

I heard that there is now research into Algae fuels as a better substitute....there's enough of the stankin' stuff in my pool to run my Farmall all summer!