# Fuel tank question YM2000



## James H Newsome (Oct 7, 2020)

I have fuel appearing on the top of the tank around the fuel cap and fuel return line. I've cleaned it off, checked the return line and after using the tractor for an hour or so the top of the tank is covered with diesel fuel. See the attached photo.

Question on the fuel cap. Is it vented somehow in its design? I assume that's the fuel tank must be able to release or take in air as the fuel is used and the injector pump returns unused fuel back to the tank.


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## bmaverick (Feb 20, 2014)

James, 

The fuel tank cap "could be" vented. I'm not really sure. Why? Because there are 2 style fuel caps. BOTH FIT. 1 is a basic cap like yours. 1 is actually a cap with a fuel gauge, being better made and beats guessing how much is in the tank! 

My machine has the fuel gauge version. After rebuilding it once, it was not vented.


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## bmaverick (Feb 20, 2014)

I was able to obtain parts to rebuild the fuel cap with gauge from Fredrick's.

This was the *BEFORE*.









This is the *AFTER. 









*Should your fuel tank have the 5-gallon or more capacity, then the gauge should work.

Here is the plain fuel cap with gasket
https://fredricksequipment.com/product/fuel-tank-cap-red-plastic-tc-155/

Here is the cap with gauge. (wow it went up in price. Was around $40 before).
https://fredricksequipment.com/product/fuel-cap-with-gauge-tc-4145
*Applications: *Yanmar 140, 147, 186, 180, 187, 226, 330, 336, 2210, 2500, 2610, 3000, 3810

The cap with gauge is also the SAME one sold by John Deere as * CH15741* for the JD650, JD750, JD850, JD950, JD1050 and others. Maybe look around for a deal.
Hoye does have it for about $65 right now.
https://www.hoyetractor.com/PROD/CH15741.htm
https://www.hoyetractor.com/PROD/TC-155.htm Or just the cap with flat o-ring
John Deere p/n CH20202

Again, to use the fuel gauge type, you need a fuel tank that is either the same depth or taller for it to work. CH19149 John Deere Fuel Tank or Yanmar 194275-04251











There are other AFTERMARKET fuel gauges too. Would these fit? Not so sure. 
One must inspect for diameter, threads to the tank and the depth of the float.
John Deere shows the others as these part numbers:
AM143171
AM143246
AM31189


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## James H Newsome (Oct 7, 2020)

bmaverick said:


> I was able to obtain parts to rebuild the fuel cap with gauge from Fredrick's.
> 
> This was the *BEFORE*.
> View attachment 64937
> ...


Thanks for all the good info. The fuel tank cap with the gauge is nice, but as you said rather pricey. If I were running the tractor non-stop for many hours it would be handy. As far as your questions "why" in reply to my asking if the cap vents the tank, I am under the impression that all fuel tanks have to vent in order to allow air in as the fuel level decreases otherwise a vacuum would form and stop the exit of fuel. Even my Snapper lawnmower has a fuel cap with a screw type vent that can be used to shut off air and moisture from entering the tank. I assume this is handy if the mower is left outside in the rain. Thanks again for all the fine information. You are a great source of info.


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## winston (Aug 19, 2008)

good information from one who knows. (41) YM2210 fuel tank vent - Yanmar Tractor Support Message Board (ymowners.com)


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## bmaverick (Feb 20, 2014)

winston said:


> good information from one who knows. (41) YM2210 fuel tank vent - Yanmar Tractor Support Message Board (ymowners.com)


When Aaron posted this ...

_The cap with the gauge vents nicely but can allow water in if left outside in the right (wrong) conditions. https://www.hoyetractor.com/PROD/TC-4145.htm 
_
I can understand his concerns. When I rebuilt mine with the fuel gauge, there is a flat compression o-ring to seal off the lens and the red cap. No moisture nor rain would get inside. My fuel gauge didn't have the screen either. 

From the Hoye or Fredrick's parts links, it's mentioned the regular caps are not vented. There is a rather large and wide flat synthetic rubber ring to seal with. With my YM2610, there is a return hose to the top area of the diesel fuel tank. Would this act like a vent of some sort? Not sure. I've not followed the hose the other way yet.


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## James H Newsome (Oct 7, 2020)

The hose "the other way" is the fuel return from the injectors. I'm no diesel mechanic, but my boat has a Universal (same as Kubota tractor engine) diesel and it has a return line from the injectors to the fuel tank also. I have boater friends who have used fuel cans in an emegercy to run their engines when they have a fuel tank issue, and they have to run a small line back to the fuel can for the overflow or surplus fuel. 

Does this satisfy the need for a vent? I don't know.


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## James H Newsome (Oct 7, 2020)

winston said:


> good information from one who knows. (41) YM2210 fuel tank vent - Yanmar Tractor Support Message Board (ymowners.com)


Thanks for posting the link. It does answer the question that there has to be a vent or the tank will form a vacuum. The question remains as to exactly how the tank vents.

I do not see how the injector return line can provide sufficient relieve to be considered a vent. It returns unburned/excess fuel so the fuel used out of the tank will always be more than the amount of fuel being returned to the tank. Also, it is not returning air, but fuel.

I am assuming that the fuel cap is designed in some manner for venting the tank since the tank on my YM2000 does not indicate a suction or collapsing problem. Regardless of how the tank is venting, I think it advisable to protect the fuel tank/cap area from rain water. If air can get in then it's also possible for water to make its way into the tank.


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## winston (Aug 19, 2008)

According to Aaron with Hoye the original design was vented through a screen with a slot in it. I am sure many no longer have the screens and as Aaron stated the new screens do not have the slot so one must be cut or leave the cap loose. You are right, the tanks do need to be vented.


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