Fuel tank cap

[Sailor2000]

I stupidly ending up dropping a small plastic cap in my fuel tank, would this ever be a problem or would it just float?
I have a racor filter water separator

Thanks !

 

[Plum]

I stupidly ending up dropping a small plastic cap in my fuel tank, would this ever be a problem or would it just float?
I have a racor filter water separator

Thanks !

If you dropped it into the fuel filler hose, could it still be trapped in that hose somewhere and give filling problems? Otherwise, if it is in the the tank and you do not have an inspection hatch to fish it out, I would forget about it.

 

[Sailor2000]

If you dropped it into the fuel filler hose, could it still be trapped in that hose somewhere and give filling problems? Otherwise, if it is in the the tank and you do not have an inspection hatch to fish it out, I would forget about it.

Thanks for your reply, my thoughts were , as it was about half an inch plastic cap seal which would float in my opinion , it’s never going to get down to fuel pick up ? ( and I keep my tanks always above half )

Or eventually I guess ? Get the whole tank pumped etc in the winter if I was ocd about it.

Would you agree ?

Thanks in advance

 

[Plum]

Thanks for your reply, my thoughts were , as it was about half an inch plastic cap seal which would float in my opinion , it’s never going to get down to fuel pick up ? ( and I keep my tanks always above half )

Or eventually I guess ? Get the whole tank pumped etc in the winter if I was ocd about it.

Would you agree ?

Thanks in advance

If the cap is polypropylene it will float, if it is polyethylene it will float, both materials arecommon for plasticcaps. Polyamide, Nylon, or polyester will sink. If you don't have an inspection hatch in the top of the tank, how will you get the tank pumped and retrieve the cap. Is your pickup pipe bore larger than half an inch? That is a very large engine.

 

[Sailor2000]

It’s definitely not going up the pick up bore / fuel line, there are actually 2 large holes that could be unscrewed on top of the tank. Engine runs fine.
Who knows what else is in there over 20 years . Thanks!

 

[Plum]

It’s definitely not going up the pick up bore / fuel line, there are actually 2 large holes that could be unscrewed on top of the tank. Engine runs fine.
Who knows what else is in there over 20 years . Thanks!

That is easy then, unscrew those access hatches and go in with a tea strainer on a stick to fish it out. While you are in, suck a sample off the bottom of the tank to see what is lurking there, I do that every year and use one of these https://www.screwfix.com/p/hilka-pr...Bh6hnX5j7fjxO_1vlbDO8d-fgzZtH2ZhoCR2cQAvD_BwE

 

[Sailor2000]

Interesting… thanks for your ideas, I’m sure it’ll be easier said than done in a 130-150l tank , but will definitely have a go

 

[ylop]

If the cap is polypropylene it will float, if it is polyethylene it will float, both materials arecommon for plasticcaps.

Diesel has a density of ~0.84 g/mL the density of polypropylene and polyethylene depends on its degree of cross linking but is almost always 0.9 g/mL. It will float on water (1.0 g/mL) but sink in fuel.

 

[ylop]

Before you go hunting in the tank - there’s not a strainer in the filler pipe is there? I have one which I discovered when trying to sample via the filler pipe.

 

[Plum]

Diesel has a density of ~0.84 g/mL the density of polypropylene and polyethylene depends on its degree of cross linking but is almost always 0.9 g/mL. It will float on water (1.0 g/mL) but sink in fuel.

Thanks for correction. I thought diesel fuel was just over 0.9

 

[Sailor2000]

Just an update , I contacted the company of the bottle to find out the exact plastic used…. It was hdpe plastic which floats in diesel fuel…. I’d like to think this would never get near the pick ups of tanks not run low?

Thanks !

 

[ylop]

Just an update , I contacted the company of the bottle to find out the exact plastic used…. It was hdpe plastic which floats in diesel fuel…. I’d like to think this would never get near the pick ups of tanks not run low?

Take some diesel. Take some HDPE (preferably the exact same component). My post 10 hasn’t changed!

 

[Sailor2000]

Just an update to my post, I probably had unbelievable luck, engineer found a jerry can fuel nozzle stuck in the filler cap which actually caught the small cap without actually going into the tank. Safe to say, all us resolved and no pump outs / frustrations needed