B7500--Has anyone else had this happen?

I have a strange situation occurring with my B7500. I noticed not long ago that as I was mowing, my fuel gauge continued to remain showing fuel as if I was not using any diesel as I mowed. After finishing up mowing, I inspected things to see what was happening and found that my fuel tank had collapsed in on itself. I had to use my air compresser and blow air into the tank with my hands covering the openning to seal it so I could pressurize the plastic tank to pop it back into it's proper position. The only way I can keep this from continuing to happen is by not tightening the fuel tank cap completely. It is almost as if the tank is not getting the proper venting and due to this it is collapsing as the fuel is consumed.

Are these tanks vented? If so where? Through the cap?

I have inspected the cap and there does not seem to be any vent holes located in the cap and the cap is clean, so I don't think that is the problem. But I cant seem to find any other venting. I hope someone else has had this problem and can share a fix. This is very frustrating. I asked my local dealer about this and they were absolutely no help and could not tell me if how the tank is vented. Thanks in advance for your help.

mendonsy said:

The tank gets air through the cap. Mine has a small hole in the center of the inside rubber piece and six openings around the outside of the cap on the bottom to draw air in.

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Thanks Mendonsy,

Maybe my cap vent holes are stopped up and just needs to be cleaned so that it will vent properly again. Do you think that could be the case? Or is there anything else that can go wrong with it to cause poor venting?

Lil Foot said:

Happened on my B7100. The cap on mine has a small hole in the center leading to a small chamber formed by a dome-shaped piece on the inside of the cap, with a similar hole. A foam insert is inside the dome. Both holes were plugged and nearly invisible. Cleared them with a toothpick, cleaned the foam, & back in business.


You drove all the way to Phoenix and asked my dealer?

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LOL...........sounds like my local dealer and yours were trained at the same place. haha. They are all smiles at the initial sale, but if you go in looking for help, they won't give you the time of day. Customer service is a thing of the past at some of these places.

mendonsy said:

One thing that can happen is that spiders get in there and build a nest. That can mess up everything. I would suggest you try blowing it out with an air hose to see if you can get it working.
It appears that the cap could be dismantled and cleaned, but I suspect that getting it apart without damaging the clip ring that holds the rubber piece in place would be interesting.

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I'll give that a try and see if I can get it cleaned out with my air hose. I use my Kubota mostly for mowing and I have some really dusty areas that I mow. I know that the bottom edges of my fuel cap where those vents are located is sort of nasty from accumulated dust and diesel, so that's probably my issue. I just never realize that those holds along the bottom edge were for ventilation. I have noticed the small pin hole in the center ofthe rubber gasket, but again, never once thought that could be for ventilation. I'll give this a try and really appreciate everyone's input on this.