MSR stove Q

[Snowflea]

Okay, here's my next techie question:

I have an old, 12-13 year old MSR Whisperlite that's had a lot of use. It's fussy but still works. However, after hearing a (confirmed) story of an MSR stove "blowing up" and severely burning someone, I'm afraid to use the stove! Should I be?

Does anyone know what "piece" generally tends to fail on these stoves? Is it the gaskets drying out, or what? Should I just throw it away? (Lately when I need a stove, I've been borrowing a Pocket Rocket anyway.)

Thanks for any and all answers/suggestions!

 

[Rick]

Hi StinkyFeet,
The parts that I have replace on mine revolve around the pump assembly. There is a check valve (one way valve) at the bottom of the pump it opens as you pump air into the fuel bottle and closes, not allowing any fuel to escape. I cannot recall if this one is leather or rubber, but as it gets older, the valve may fail and allow fuel/air or both to leak through into the pump chamber and then out of the pump housing. There is also a small rubber o-ring at the spot where the stove connects to the fuel pump, as well as a rubber washer where the pump connects to the bottle. Any one of these could fail over time allowing fuel to leak out.
There are no rubber or leather parts on the stove itself, to wear out.
To be completely safe, I wold just order a new pump assembly. It appears MSR has changed their style, but if safety is the big concern, then $35 isn't a lot to spend. MSR PUMP
You could order also the parts kit for around $15 if you wanted replace them yourself. I'd be glad to help you out if you'd like. Just PM me. I used to work on larger similar pumps, so I am pretty comfortable around them.
Rick

 

[TomD]

Msr

Liquid fuel stoves don't just "blow up," so I am wondering what you are talking about. A canister will explode if overheated, but a liquid fuel stove like a Whisperlite has a separate fuel bottle. Unless you have a leak at the pump, I don't see how you could set it on fire. I know this firsthand because it happened to me. I put the fire out before it did much damage to the pump. I have an old XGK (mid 80s vintage) with the yellow plastic pump. I got a rebuild kit from MSR after calling them about it a couple of years ago. The kit was mostly a few washers for the pump and the valve, if I remember right. The fire was caused by my failure to attach the pump properly and not noticing it leaking until the stove was lit.

I'd pull the stove apart, check the seals on the on/off valve, check the fuel nozzle, replace all the soft parts on the pump, then test it out.

MSR sells rebuild kits online and in stores. In my case, my XGK is so old the kits don't fit it due to design changes, so you'll need to check if any changes have been made to your model. If so, call MSR and talk to them.

 

[DougPaul]

Liquid fuel stoves don't just "blow up," so I am wondering what you are talking about.

Just a nit--some liquid fuel stoves can blow up. The MSRs all use cold fuel tanks and can only blow up if you way overpump them. (Some old, old Sigg bottles failed near the neck from this problem.)

Some liquid fuel stoves (eg Svea 123, optimus 8R) use heat from the burner to pressurize the tank. The tank can overheat and blow up. Typical causes are removing the heat shield (8R), too big a pot, or a windscreen.

Doug

 

[TomD]

Stoves

Doug, You are right, I wasn't as clear as should have been. I was referring to stoves with separate fuel bottles. I've got a Svea 123 so I can see how it could possibly go off, but I never had any trouble with mine and never heard of one blowing up. I suppose if the nozzle failed or leaked at the base, you'd be in big trouble from the flashover or if the overpressurization valve failed and started spraying fuel all over the place.

 

[peakbagger]

The predominate failure of whisperlites that can cause fuel leaks is the O Ring that the brass fuel connector slides into. When the Oring fails, gas can leak/spray out of the fuel pump assembly when it gets pressurized. I have seen cases where the O-ring initially sealed, the stove was started, then for some reason the fuel bottle was shifted and the O-ring starting leaking causing a fire.

Determining if the O-ring is near failure is difficult, It requires good lighting and possibly a magnifying lens. The much easier technique is to follow the directions and use silicon grease on the brass insert and the O-ring should last a long time. I used to install a rebuild kit every fews years when I used the stove a lot.

There were also failures where Non MSR bottles would be used with MSR stoves. They would initially hold pressure but in the right conditions, would release a gas spray at the seam when heated up. This could cause an "explosion"

The other problem that I believe occured on MSR dragon fly stove only (but may have on others) is a problem with the connectors that allow the pump to be rebuilt. They uses a plastic design and part of the casting would fail on the pump body. If the pump were pumped up while the stove was running, it is conceivable that the pump head could disengage from the pump body. At one time dealers would replace the part in question with an upgraded one for free but not anymore.

 

[oswegatchie]

Although I use a Peak I stove rather than an MSR, I present the following cautionary tale, because the overall design is the same- both use a separate fuel tank.

We were canoeing along a river in central New York one April day when we decided we needed a cup of coffee to take the chill off. The river meandered through a marshy/swampy sort of place, and landing sites were few and far between. We settled on a spot on a grassy bank that was barely space enough for us and the stove. Moments after lighting the stove, it began spraying fuel from the connection between the tank and the pump. Said sprayed fuel promptly ignited, and it took but a nanosecond to deduce that there was no solution to our problem but to nudge the entire assembly, posthaste, into the river. The O-ring, which I had never changed and had been in use for probably five years, had deteriorated. Happily, I had a spare with me (!), and after changing it out, the stove relit. (Peak I stoves are heavy, but reliable). Apparently, I had been overzealous in tightening this connection when refueling, and had mashed the o-ring into ineffectiveness.

I found that my hardware store has the o-rings in stock for about a dime apiece, and I now routinely change it every second refueling. And of course, I'm careful about not tightening beyond snug.

 

[DougPaul]

I've got a Svea 123 so I can see how it could possibly go off, but I never had any trouble with mine and never heard of one blowing up. I suppose if the nozzle failed or leaked at the base, you'd be in big trouble from the flashover or if the overpressurization valve failed and started spraying fuel all over the place.

The filler cap of both the Svea 123 and the Optimus 8R includes a pressure relief valve to prevent a tank explosion. When this opens, either due to deterioration of the valve or overpressure, you get a spectacular torch. (Or so I have read--haven't seen one myself). While technically not an explosion, it might tend to "warm up" the surroundings.

Another way to warm things up a bit too quickly is to open the fuel bottle on one stove while another (or any open flame) is running nearby in an enclosed area. The flame from the second stove ignites the fumes from the first giving you a nice little fuel-air explosion. Tents etc have been blown up this way...

Doug

 

[Mad Townie]

The filler cap of both the Svea 123 and the Optimus 8R includes a pressure relief valve to prevent a tank explosion. When this opens, either due to deterioration of the valve or overpressure, you get a spectacular torch. (Or so I have read--haven't seen one myself).

I have. "Spectacular" is just about the perfect word!

All I can say is my hiking partner and I were thankful for redundant systems that January evening.

 

[TomD]

svea 123

I have one of the accessory pumps that fits over the filler valve on a Svea 123 to pressurize the tank at altitude. I have read some advice about not using it at all or being careful with it for the very reason you describe-the overpressure valve goes off and sprays burning fuel everywhere-a good reason not to run a stove in a tent regardless of what kind it is.

 

[peakbagger]

I saw a Svea blow a relief valve once on a winter campout where the stove operator rigged up a tight heat shield and was heating a large pot with the fuel valve wide open. The combination reflected enough heat back at the tank that it overheated and opened the relief valve. The stove flared up big time and was dropkicked out of the shelter and into a snow bank. Once it cooled down, we got it relit.

 

[Rick]

I also had the aux. pump for my old phoenix backpacker (similar to the 8R) but my blowout valve wasn't a blowout valve but rather a mechanical relief valve. I had to loosen the nipple with the tiny supplied wrench to release pressure and then re-tighten it. I have used the stove in the self-pressurization mode, but I was always a little too impatient awaiting the pressure to build up from heat hence the pump.

There is a place in LA, CA A&H Stoves that still carries OEM parts. I have the number some where if anyone needs it.