Kevin's Question:

Recently, I was given a backpacking Primus stove that is rather old and I'm not sure I know how to use it. I'm hoping you'll be able to help. The stove is a light blue, metallic color and measures 5 x 5 x 3.25 inches. On the top is an old Primus logo. Embossed on the top is"8R" and "Made in Sweden."

Kevin Berry
San Antonio, Texas

Expert Answer:

On the basis of your description I recognize this as a style of stove I used years ago myself. Although outclassed in some ways by today's stoves, it is a good enough unit to resurrect, especially as the price was obviously right. However, this is one gift horse who's mouth you'll want to look in: Beware of any stove whose history you don't know!

Test the stove outside with a fire extinguisher handy and a buddy in case you get into trouble. If in doubt seek professional attention (see phone number below).

That said, my recollection is that the 8R is actually an Optimus stove, but there was a time when the distinctions between the brands were a bit blurred. If this is the unit I'm remembering, it burns white gas using self-pressure. You fill the circular cup under the burner with fuel using an eyedropper, or by carefully using the pourer hole in a screw-top metal bottle such as Sigg or MSR. Close the valve (square stem at the base of the burner) by turning it to the right with the key, then light the fuel.

This process heats the burner and tank, and generates pressure without a pump; when you open the valve there is enough pressure to force fuel into the burner. Enough heat enters the tank during use to maintain this pressure. Two points to remember: Be sure to fill the cup completely, and don't open the valve until the fuel is almost burned away. If you are too hasty, the stove will flare up.

To eliminate the need to pour fuel into the cup, you can get a device called a Mini Pump that fits a modified filler cap. The Mini Pump allows you to pre-pressurize the tank — opening the valve will let fuel from the tank fill the cup. You then close the valve, light, and reopen just before the cup burns dry. The pump also makes it easier to maintain pressure in cold weather.

Be careful not to turn the valve too far left, because this would push a needle up from inside the jet to clean it — thus obstructing the fuel flow. This needle is a key part of the system, and if before lighting you turn the key left and cannot see the needle come up in the jet, you have a problem. Needles are available but you need to know what you are doing to install them.

The other part to be wary of is the tank lid and the valve in it — if the valve has blown at some time in the past, the exiting fuel vapor will have ignited and probably melted the washer in the valve so it no longer seals. As a result it will leak and may catch fire again.

If you need parts or service, contact A and H Enterprises in Tustin, California: (888) 456-0748.