black particles found in the fuel filter

[rejesterd]

I have a 2011 Yamaha F50 TLR.

Yesterday I was doing my routine spring maintenance to get the boat ready for the season. I went to change the on-engine fuel filter, and found a good amount of black particles in the filter cup. After I emptied the cup, I pumped some fuel out of the filter assembly cap (which I left attached to the inlet fuel line) with the primer bulb.. a significant amount of more black particles came out. So it doesn't look like it was just a tiny amount that had slowly built up in the cup. It basically looks like a fine black powder.. it's not clumpy, and I saw no water in the fuel.

I'm looking for guidance on how to determine the source of this contamination. I'm not sure if the black stuff is coming from the lines on the engine, the lines between the engine and the fuel tank, or from the tank itself. I'm going to take a closer look on Saturday. For reference, I have (what appears to be) a fiberglass fuel tank and a 10-micron fuel/water separator filter in between the tank and the engine (which was replaced last fall when I was winterizing it). Like every year, the boat sits from mid-September to mid-May. As part of my winterization process, I fill the fuel tank 7/8 full of E10 fuel and add Yamaha fuel stabilizer. I've used only E10 fuel since I've had the boat, but this is the first year I've seen black particles like this.

My current plan is to hook up a new primer bulb assembly directly to my boat's fuel tank, and pump out some fuel into a clear container. If black particles come out, then I would assume the tank is the source of my problem. If no black particles come out of the tank, then I'm going to hook the other end of my spare bulb assembly line directly to the engine. Then pump the bulb and see if the black particles stop coming out of the on-board fuel filter assembly cap. If they stop coming out, I think I can assume that the particles are due to rotting fuel lines between the fuel tank and the engine (and I'll simply replace them). If they don't stop coming out at that point, I think I can assume that the fuel lines on the engine itself are rotting. I suppose that could be due to using E10 fuel. However, the owner's manual says that the engine is calibrated to handle E10 fuel. I assume that means the engine lines are rated to handle a small percentage of ethanol.

Once I find the source of the contamination, I will inspect the mechanical fuel pump and drain the vapor separator to see if the black particles made their way in there. If I find black particles in there, I will get the rebuild kit for the VST and monitor performance on the water after rebuilding the VST. If performance still suffers, and I go back and confirm that no more black particles are coming in, I'll send the injectors to be cleaned.

Does that sound like a reasonable strategy?

Thanks.

 

[GA_Boater]

With these black particles in the engine filter cup, the source would have to be somewhere between the water separator/fuel filter and the engine filter.

You don't say what motor this is. Some are known to have fuel system deterioration issues.

 

[rejesterd]

With these black particles in the engine filter cup, the source would have to be somewhere between the water separator/fuel filter and the engine filter.

You don't say what motor this is. Some are known to have fuel system deterioration issues.

Thanks. I edited the post probably while you were writing your response. Sorry about that. It's a 2011 F50 TLR.

So you think the 10-micron separator filter would catch these particles if they were coming from the tank (or the line between the tank and the separator filter)? That's what I'm hoping, as the best case scenario is I just have to replace the bulb assembly and the line coming from the separator filter (though I would probably replace the line from the tank as well, since lines are cheap).

 

[GA_Boater]

You can see the black grit, it's far bigger than 10 microns. So yes, it should catch the black stuff.

One micron is equal to one-millionth of a meter, or 1/26,000 of an inch. On average, the human eye cannot see particles that are smaller than 50 to 60 microns. Particles that are 10 microns or less are considered respirable and can settle deep into the lungs – often causing adverse health effects.

This has been a presentation of the iBoats science department.

 

[rejesterd]

Very good, thanks again.

 

[dingbat]

Nine times out of ten it's the hose (grey) running from the primer bulb to the fuel pump.

The after market grey hose common on primer bulb replacement kits is a known culprit. Best to buy an OEM primer bulb and a section of good quality, A1 marine fuel line and fab your own assembly

 

[rejesterd]

Nine times out of ten it's the hose (grey) running from the primer bulb to the fuel pump.

The after market grey hose common on primer bulb replacement kits is a known culprit. Best to buy an OEM primer bulb and a section of good quality, A1 marine fuel line and fab your own assembly

Thanks. I don't have the gray kit. Not sure if the bulb is OEM, but I like the idea of buying the hose separately from the bulb.

 

[Texasmark]

Different engine supplier, my hoses went to pieces at 10 years....your fuel lines are dissolving. Replace all your engine fuel lines, fuel pump diaphragm and fuel line and squeeze bulb from fuel tank to engine...and any more rubber in the fuel line.

While you are at it drop the bowls on your carbs and see if particles are there....if so clean them out and don't forget the compressed air for blowing things out when finished. I had an intermittent problem on my 2004 90 Merc 2 stroker in 2014 and found some of what you describe in the bottom of a fuel bowl and had I not been blowing out I would never have found it...lodged in the high speed jet, out of sight.

 

[rejesterd]

Different engine supplier, my hoses went to pieces at 10 years....your fuel lines are dissolving. Replace all your engine fuel lines, fuel pump diaphragm and fuel line and squeeze bulb from fuel tank to engine...and any more rubber in the fuel line.

While you are at it drop the bowls on your carbs and see if particles are there....if so clean them out and don't forget the compressed air for blowing things out when finished. I had an intermittent problem on my 2004 90 Merc 2 stroker in 2014 and found some of what you describe in the bottom of a fuel bowl and had I not been blowing out I would never have found it...lodged in the high speed jet, out of sight.

Thanks. I'm not the original owner, but I assume the hoses are now right around 10 years old. Hopefully I can get it all cleaned out and get out on the water tomorrow.

 

[rejesterd]

After taking a closer look at things today, it seems the black particles didn't get to the vapor separator.. nothing but fresh-looking fuel came out when I drained it. So I'm just going to replace the hoses going from the tank to the engine, and inspect (and possibly replace) the mechanical fuel pump diaphragm. Thanks again for the suggestions.

 

[Texasmark]

Nine times out of ten it's the hose (grey) running from the primer bulb to the fuel pump.

The after market grey hose common on primer bulb replacement kits is a known culprit. Best to buy an OEM primer bulb and a section of good quality, A1 marine fuel line and fab your own assembly

I had the grey OEM hose go out on my 2004 at 10 years along with the internal hoses as I mentioned herein. It developed some kind of tan caked material internally. Replaced it with automotive fuel line and an OEM Quicksilver squeeze bulb. I replaced the whole line.

 

[rejesterd]

I bought a new bulb and some black A1-15 hosing. Pretty expensive, but I assume there's a good reason for that.