JD 5210 fuel tank under vacuum

[2fast2]

After several hours of bush hogging at 2400 rpm engine speed, I parked the 5210. When I went to refuel, and opened the cap, there was a LOT of negative pressure (and I noticed the top of the fuel tank sucked down on the right side.) At this point, the fuel level was down to 1/4.
I can't tell whether the cap is supposed to be vented or not. There is no obvious hole. I'm wondering whether the cap provides the vent or whether there is some other vent which might be clogged?
Can anyone help?
Leaving the cap loose probably isn't the right answer :laughing: Sort of like telling someone to turn up the radio when they complain of the funny noise the car is making :confused2:

 

[kennyd]

I am not sure if the cap is vented or not, but there is a tank vent, part #"s 24, 24, and 26 in the diagram below. Make sure the hose is not pinched.

 

[2fast2]

Thanks kennyd. I'll check that hose. That makes much more sense than a problem with the cap.
How did you get that diagram? That is extremely helpful to me.

 

[kennyd]

Register for free at www.jdparts.com

It is the same basic system used at the dealers parts counter. One hint is to "think like a parts guy"

I made a simple tutorial here: Picasa Web Albums - Ken - JDParts Tutorial

 

[2fast2]

Thanks, I spent some time at the web site and I actually have the other fuel tank, not the one with the vent hose you pictured. In the other picture, I can't tell if there is a vent anywhere or not. Guess I will ask the dealer.
Is there any way to search by VIN rather than model #?

 

[kennyd]

Is there any way to search by VIN rather than model #?

Maybe a dealer can...But usually in JDParts it gives serial number breaks for major changes. Sorry my picture did not help

 

[2fast2]

An update in case anyone ever has a similar problem and searched and finds this thread:
There are 2 different fuel tanks for the 5210, and mine does not have the vent tube shown above. According to the mechanics at the local JD dealership, this version uses a vented fuel cap, whereas the vented tank uses a non-vented cap. Makes sense.
The two caps listed look completely different, one is outside threaded and the other is inside, they are different diameters, too.
I had noticed that the cap off my Gator XUV 850 D looked like it would fit, and was vented. The dealer didn't have the one for my 5210 (which was around $25) but he had a Gator diesel cap, which was $11.50.
It fits MUCH better than what was on my tractor. I suspect this never had the right cap from the previous owner(s). I've owned it about 6 years and 500 hours and never had a problem, probably because I never had the cap on quite tight enough to seal completely. I expect the vented cap to solve the problem for me.
Jim

 

[kennyd]

Good info Jim...I do see now that there is a serial # break listed in JD parts-looks like you have the early version. Here is a picture of what you should have, Sorry I missed that before.

 

[2fast2]

Yes, the tank looks like that, but the cap doesn't. My tank has external threads for the cap (the cap is threaded on the inside and is flat on top with finger grips around the circumference.) The pictured one has a grip-bar on the top and has threads on the outside like an automobile gas cap.
But I have a cap that fits well and has a vent, and hopefully my problem is solved.
BTW the cap I had looks similar to the cap on my GT275 mower except it is marked diesel instead of gasoline.