2001 F115 VST Fuel Contamination

[finaticfishing]

History: I have become very good at pulling and cleaning VST tanks and injectors, thanks to having twins and great reading and help from this forum. The value of the Yamaha Master techs and experienced people here to me is invaluable. I would like to say Thank You to all the people who frequently help the people here. In saying that, roughly once a year I do my annual VST tank cleaning service along with all the regular filters, oil, grease, plugs, etc. After this annual cleaning, in 15 hours one engine was plugged and cleaned. Same engine, another 10 hours the HP fuel injector pump in the tank failed. Replaced and cleaned the tank while inside.

Questions are: I had a black powder like substance in the drained fuel from the VST and fuel lines to the VST tank. It is definately a powdery substance. When I would shake the bowl of fuel it would look like a cloud of black in the fuel. I can only guess this is what plugs the VST filter. Also, if I can see these particles, would this not be caught by the 10 mic racor or the onboard filter? All the fuel lines have been replaced up to the motor with the new USCG approved ethanol approved lines. I am running ethanol gas.. Is it possible one of the older Yamaha fuel lines after the onboard filter is deteriorating? Could the dust be from the HP fuel injector pump failing? What does experience say?

Thanks for any help.

[boats.net]

Could be rubber dissolved by ethanol gas, check the inside of fuel hoses, fuel pump diaphrams in lift pumps and filters.

[rodbolt17]

its possible that its brush dust.
it is a blow through design and gasoline passes over the ameture and through the brushs on the way out.
its also possible that the E fuels are damaging the rubber parts.
some call it the EPA mandate.
we calll it the US govt marine technician stimulous program.