There are some compelling reasons why you would want to buy the new pump, but it isn't necessary. If the old pump is working then there's really no need to replace it. I would give the old pump a thorough inspection most especially looking at the O-rings (the big O-ring where the pump screws into the fuel bottle is the most critical). If you see any cracking of the rubber or any cracks on the pump itself I would replace it. This is not a warranty issue since it's most likely due to normal use. If you suspect it is a warranty issue, call Cascade Designs at (800) 505-9500 and they will issue you a Return Authorization Number. You will need to send it back and, after they inspect it, determine that it isn't a warranty issue then they will repair it for a reasonable fee. They can help you over the phone if you have specific questions...

The new pump will allow you to simmer better (not like a canister stove, but gives you one full rotation of adjustment vs. the old pump that gives you no rotation adjustment). It's also much more durable, won't spray fuel when you release the pressure after unscrewing it, and is much easier to maintain (no leather plunger). It also comes with a new windscreen which is a $10 value.

My opinion is the $35 for the new pump is money well spent and will upgrade your stove to the latest version of the Whisperlite. The most resent updates to the Whisperlite have to do entirely with the pump, not the stove.

I got my whisperlite int'l 2 years ago and it has this pump in it. Perhaps your stove is older? Either way, unless there is something wrong with it, I don't think you need to replace. I don't think MSR will do it for you either, especially if the one you have now works. Look at the Q & A below this for the advantages of the new pump.

I would recommend getting a new pump. If anything is broken on the original pump it should be considered unserviceable and discarded. The reason is you are dealing with a very volatile fuel (white gas) and fire. If any of the fuel leaks out or the pump doesn't seal properly to the stove, you risk having the whole thing light up like a Christmas tree. I've seen it and it's not pretty. There are some neat advantages in getting the new pump anyway. For one, it's more durable. Two, it gives you better simmering capability, and three, it comes with a brand new windscreen. It's well worth the money and will update your Whisperlite significantly. It is one of the few upgrades that is strongly recommended. The Standard Pump is what you want...

Before you start replacing parts or the entire pump, apply a small amount of petroleum jelly on the pump leather. This is the part on the end of the plunger that actually forces air in to the fuel bottle. Work the pt in, remove any excess, then pump until you get the air flowing again. The next step would be to replace the rubber o-ring where the plunger seals @ the fuel bottle. This part normally doesn't need to be replaced unless it becomes brittle or cracked.

The best thing to do would be to take your stove to a store that sell MSR products & see if the pump is interchangeable. Take along your empty fuel bottle to make sure the threads are also compatible.

What I believe you're seeing and referring to in the picture is not the fuel intake but the check valve. If you look closely, you will see a part of the fuel uptake tube on the left (more visible on the Dragonfly pump pic). This flexible line rests on the bottom of the fuel bottle, regardless of MSR fuel bottle size, when aligned for stove use. Because of this setup, less than 1/2tsp of fuel remains unused, at least in my experience, and I am neither careful nor particularly conscientious of the fuel bottle's placement on the ground.

It will. Just choose the Dragonfly pump in 'Select options'.

I've never had a problem with it and use it all the time. Figure out where it's leaking from and check that that part's secure, and you might want to just pony up for a new one. Leaking fuel is not a risk worth $35.

Here's three links to the information you're looking for:http://www.backcountry.com/store/CAS0376/MSR-Fuel-Pump.htmlhttp://sales.liveperson.net/hc/s-9551721/cmd/kbresource/kb-6338232607920599444/view_question!PAGETYPE?sf=101133&documentid=239532&action=view&VisitorProfile=BCS&MESSAGEVAR!home=no&MESSAGEVAR!cookie=nohttp://sales.liveperson.net/hc/s-9551721/cmd/kbresource/kb-4986987583145535645/view_question!PAGETYPE?sf=101133&documentid=239589&;action=view&VisitorProfile=BCS&MESSAGEVAR!home=no&MESSAGEVAR!cookie=no

This pump works by pumping air in, not fuel out. Since air or gaseous fuel is much more compressible than liquid fuel, it will take longer to pressurize the emptier it gets. Seems like filling the fuel back up would tell you whether that was the problem, otherwise it's probably broken. Make sure it's screwed on right too. You will also want to be sure that the internal fuel cup in the pump is lubricated - pull it apart and put a bit of oil or spit on it to make sure it's making a good seal.

First Class Mail International Package costs $9.85. Priority Mail costs $49.95. This is based on a one pound package.Here's the USPS website page as of 9/13/2008:http://ircalc.usps.gov/IntlMailServices.aspx?Country=10211&M=2&P=1&O=0&sd=1