Water in fuel???

Cord · Aug 9, 2016

I had a skidsteer with a Deutz diesel engine that had a miss at certain times. Sometimes the engine would really lay down and refuse to rev up only to run great a moment later. Almost like it was sucking air and would then bleed out. I'd swear the problem was position sensitive and if the machine was turn just the right way it would develop a miss. I was never able to identify a particular pattern to this so it could be nothing. Other times it would run good but you could hear a miss. Anyways, the machine ended up catching on fire and burned. During the environmental clean up we went to drain the tank and I noticed some water at the very bottom. Not much, but enough that I could see it in the stream before the fluid turned red. I suspect the drain plug is lower than the fuel pickup which allowed the water to pool at the bottom of the tank.

I now have a new(er) machine that's actually identical to the old one. Has 1,000 fewer hours and runs a lot better. When I got the machine I noticed the fuel gauge was reading empty so I stopped by my fuel tank and topped it off. The gauge still read empty which I later diagnosed as a defective gauge. I'd guess that I put in 5 gallons into a 16 gallon tank. Now the new machine is running with a miss. Coincidence?

This got me thinking about water in the fuel. The storage tank is a 275 gallon oil tank with a hand pump with a filter. I'm pretty sure it's not a water absorbing filter. The settling bowl on the filter has a little grit in it, but I see no water. The fuel is red, maybe a bit darker than I'd like to see. The fuel is probably 2 years old and the tank is about 1/3 full. Although the fuel is old, the older machine definitely had the miss back when the fuel was fresh. Neither machine has a water-in-fuel light.

My mower is also Yanmar diesel powered and it's running great. This mower is also fueled off the same tank.

4570Man · Aug 9, 2016

What caused the SS to burn?

Cord · Aug 9, 2016

Machine had problems starting. First appeared when it was cold and got worse to the point that it wouldn't start when it was warm out. Was trying to remove the injectors so we could perform a compression test but one injector was stuck. Even tried to pull it using a ratcheting load binder and ended up breaking the puller. Short of having to pull the head we were trying to heat the injector. The flame from the torch caused the cloth jacket on the return fuel line to catch on fire and the jacket burned like a cannon fuse. It was a small fire and could have been put out if I had some gloves on. It wasn't long before the burning jacket reached the belly pan where it found some spilled fuel that had soaked into the dirt. Still wasn't much of a fire until it overheated the fuel filter. Once the filter popped it sprayed hot fuel everywhere and the machine literally exploded in fire. Fire went from 12" high to 6' in less than a second. Took 3 fire extinguishers and a garden hose to put it out.

RjCorazza · Aug 14, 2016

Contaminated fuel can be a real hassle. With 2 year old fuel (not a problem by itself), 1/3 full tank, and running issues, I would think water could be real possibility. With confirmed contaminated fuel it's best to "go big or go home" and totally drain / filter the equipment and storage tank. Perhaps you could put a water block filter on the tank and see what happens. The small canister type water block filters fill up quick and will lock up a hand pump with no room for doubt.
I got 350g of fuel free several years ago that was 2-3 years old in unknown condition. I filtered it several times (water also) and used it out of 55g drums. Unfortunately I screwed up and didn't use a water block filter for the last bit of fuel from the last drum, and got water in my zero turn mower fuel tanks. After draining the machine tanks I filtered the 10 gallons with a water filtering funnel (very effective), and again with the spin on water block cartridge. I think I also added some of that "fuel 911" stuff for good measure.

Rock knocker · Aug 14, 2016

Algae can also cause water in the fuel thru digestion by the formula nHC+O*2> H*2O+CO*2. A good biocide can help, and certainly not hurt.

I'm partial to Bio Kleen by Power Service Corp, but there are other similar products

Cord · Aug 15, 2016

I pulled a sample the other day and although a tad bit dark, the fuel was crystal clear. No signs of free water. I threw some diesel conditioner into the tank and it seems to be running better.