Pros: Original manufacturer, Cheaper than a new stove
Cons: Plastic is easy to break
If the time has come to replace your fuel pump on your MSR Whisperlite stove, it's best to go with the original for the replacement. That's what you get with the MSR Standard Fuel Pump. This pump replaces the pump that came with the Whisperlite and lets you pressurize your fuel bottle so you can be up and cooking again.
While the actual stove part of the Whisperlite will likely last for years with some simple maintenance, the fuel pump portion of the stove has a greater chance of malfunctioning or breaking. That's why this pump is sold separately. You can pay about $30 to replace the pump as opposed to buying an entire new Whisperlite stove for close to $80.
There isn't too much to this replacement pump. It is the same pump that comes with the Whisperlite stove and it screws into the standard MSR fuel bottles and connects, via the Whisperlite stove's house to the stove itself.
You give the bottle several pumps, which pressurizes the fuel bottle and which is connected to the Whisperlite stove. Once you start the stove, the pressurized fuel flows through and keeps the stove going. Occasionally you'll have to pump it up again to maintain the pressure to keep the fire on the stove going at its peak efficiency.
The best way to make sure your replacement fuel pump won't need replacing itself is to take good care of it. The majority of the pump is made from plastic so first and foremost when you are using it, be gentle because plastic can break. After that, just make sure you are properly maintaining the seals and gaskets in the pump. Keep them lubed and in the case of the small leather gasket, moistened so that they don't crack or leak and reduce the effectiveness of the fuel pump.
Other MSR stoves
The Whisperlite isn't the only stove that uses the standard fuel pump. It also works as a replacement on the Whisperlite Internationale, SimmerLite, and XGK stoves.
In the many years of having a Whisperlite stove I've only had to get the replacement pump once and that was because of a combination of cracked gaskets and a bit of over eager pumping that left the pumping mechanism damaged. At that point I figured it was just easier to replace the fuel pump instead of trying to fix it.
The new pump worked just as well as my original with my Whisperlite and since then I've made sure to be a bit more gentle when pumping and I do regular maintenance on the gaskets to keep them in good working order.
If you've broken your fuel pump with your MSR Whisperlite stove, you really should get a replacement pump instead of getting a whole new stove. It's cheaper and the pump works just as well as the original since it is an MSR product.