Fuel Contamination

[pmccarthy]

I just had a fuel contamination problem with my ride-on mower. I buy the fuel from the same outlet where I buy my Mogas for flying, though from a different pump and using different jerry cans, hence some concern.

 

The mower would run for 20 minutes then stop. I took off the fuel filter and noticed there was no flow from tank, just a drip. I left it dripping while I went into town and bought a new filter. When I came back there was a mass of white ice crystals at the end of the fuel line, along the outside of the line and on the ground beneath it. These were ice crystals and very cold, though the day was warm about 20 degrees.

 

If this is simply water contamination then my Mr Funnel should filter it out when I fuel the plane, and I should see it when I do a fuel drain. But I am concerned that it may be some other contaminant that could get through and cause the same stoppage that I had in the mower.

 

 

[Guest Maj Millard]

Hmmmmmm..................

 

 

[jetjr]

A few cents worth

 

Had a very busy winter on job site running 15 + small petrol engines for weeks on end.

 

CONSTANT fuel contamination problems, crystals, jelly, greasy type white stuff - all fairly fresh fuel, largely E10 types, some times week old fuel was clogging screens, filters, fuel lines and jets.

 

Often would start and run well but slowly falter under load then not restart. Might run again no problem later on.

 

Guys are now very particular with hygiene but still get problems even with 98.

 

Ive got a real lack of trust with ULP from the average servo and symptoms are scary if transferred to aircraft.

 

 

[rgmwa]

Bad enough in cars too. The mechanic got 10 litres of water out of my fuel tank and engine a few weeks ago. The fuel supplier paid for the work, but the servo just lost a 20 year premium ULP customer. The engine sounds rougher now too, but maybe that's my imagination.

 

rgmwa

 

 

[Guest Maj Millard]

Don 't forget those fuel- drain checks folks !..............................Maj.....

 

 

[Dafydd Llewellyn]

Do you know how to check if the fuel contains alchohol? (add a small amount of water to the fuel test sample. If you get a much larger amount of water as a result, it had alchohol that had absorbed some water, but not quite enough to make it separate from the petrol). Alchohol in the fuel is always in danger of separating, if it has time to absorb sufficient moisture from the air - so it's not a good risk in a flying machine. If the alchohol separates, your engine will be running lean, because straight alchohol needs a larger main jet to give the correct mixture.

 

Also, an in-line filter of the common styles normally seen, is asking for fuel starvation due to filter blockage - an accident going somewhere to happen, in fact. A gascolator (fuel sediment bowl with a simple brass screen at the top) is vastly less susceptible to clogging; and it tends to self-clean whilst the aircraft is not in use - the garbage falls to the bottom of the bowl, and gets removed when you do the morning fuel drain check, along with any water that has made it to the sediment bowl. Get one that has a drain valve fitted to the sediment bowl, and drain a bit from it after every refuelling and at the daily inspection.