Consider this Norm, I just had repaired a Generac generator back in June and customer had use it several times afterwards. Just brought it back last week with fuel running out the air cleaner. When I pull the carb to clean it I found water and rust balls. The water I could easily explain without looking but it is the rust balls that me doing additional checks.

I made sure the tank filter screen was in place. Now there only one place in the whole fuel system that the rust could have from other than an accidental tank fill-up. That the carburetor fuel inlet tube. It was the only thing was steel. I cleaned as clean as I could and told if the rust balls showed again I need to put on a new carburetor.

This way I would have that old carburetor to try a replacement brass inlet tube idea on.

It easy to check the customer's fuel for Ethanol content. Find a 250 ml test tube or container with ml markings. Needs to seal-able or moisture from the air will affect the test. Fill the first 50 ml with water then finish filling to 250 ml line. Now cap it and shake it to mix. Set aside to settle for a few minutes. Once settle over 50 ml is Ethanol content divided by 2. Otherwords if you have now a 70 ml water line that would be 70-50 = 20 ml. 20 ml divide becomes 10 % as you using double the amount of fuel during the test. You can use an 125 ml test tube but using the larger tube uses twice the amount which gives a better and easier to read reading.

BTW be careful if you test your supplier fuel at the pump. I had one to cuss me out saying his fuel was 100% pure fuel. He stood there while I ran second test which it failed a second time. He order me off his property. But the very next day he came to my shop with an apology as he called his supplier and they tested his fuel and they came back out pumped his tanks out as they delivered the wrong fuel.

Now I not against Ethanol fuel blends just like to know that what I getting as I need to take additional protective measures with Ethanol blends like a tightly seal contain as it can and will absorb moisture while in storage. Now here a lot of techs blaming all fuel problems on Ethanol which is not the case as even as non Ethanol has additives so it can meet EPA requirements here. I would think this is the same in a lot of other countries too.

The level of Ethanol in the fuel can cause you problem especially if above 10% as many the OEM fuel parts are only tested and rated for 10% or less blends. Here in my area the EPA is introducing a 15% blend so I will see more fuel problems. All ready seen some bubbling fuel this year in those clear fuel filter on some Kohler Courage single cylinders causing running problems. The only solution was either changing the fuel or shielding the fuel lines.