(After figuring out a hillbilly way to compensate for worn teeth on the wick gear, I did eventually realize that if you vary from the manual’s instructions and tension the gear either higher or lower than recommended, you can skip those worn teeth altogether. If you’ve read this before you might notice that I no longer recommend using HEET in the fuel.)
The typical warranted lifetime of a kerosene heater is one to two years, and if everything works for two years you are very lucky. I can say that a lot of things said about these heaters is a bit of hype, speaking from my own experience as a person who has depended upon them, in Indiana, for about seven years now — long enough that I’m forgetting details already. Some of the perks break down quickly, and other important parts of the machines break down far too soon and would usually require you to buy a new heater. There are things you can do to keep these heaters going, and the evidence I present is the Sengoku OR-77. I bought this heater with a two year limited warranty about seven years ago and it is working fine, but that’s only because I figured some things out about how to keep it going.
The first thing to fail will be the wick. If you buy the reasonably priced kerosene from your local gas stations instead of the doubly priced kerosene from Walmart (guaranteed water free) you will pick up a little water in the fuel. Many people are recommending adding a spoonful of HEET Isoprophyl alcohol gasoline treatment with each new tank of fuel to remove the water from the kerosene. These people say to wait for twenty minutes before you light the stove, so the alcohol has time to sort the water out of the fuel. I have followed that procedure for several years and as yet have not seen it work. The more HEET you add to the tank, the sooner the wick becomes waterlogged and useless. After thinking about this for a long, long time, I finally realized that HEET was designed for use in internal combustion engines and everyone just assumes it will do the same thing for kerosene stoves. What HEET actually does is pull the water from the bottom of the fuel tank to the wick, where the alcohol burns off and leaves the water behind. An internal combustion engine can spit the water out if it’s thinned down alcohol. Wicks don’t do that. Modern kerosene heaters are actually designed so that the wick well sits above the bottom of the tank, separating the wick from the water that will settle to the bottom. Draining out that last bit of fuel after a clean burn will also remove water from the tank. I recommend using a water filter funnel to clean the fuel as you fill the stove. Mr. Funnel has been a good investment.
About every six refills I let my stove burn until empty, outside on the porch, until it goes out or almost goes out. Then I brush the wick clean with an old toothbrush, refill it and bring it in the house and after twenty minutes I start it up again. This system has served me well. But, since this is the stove I use the most, every year I replace the wick. Wicks become charred and they also do collect water, no matter how carefully you tend them, so a winter of use is about the most you can expect from a wick. I buy my replacement wicks at Headley’s DoItBest Hardware in Greencastle, Indiana. If you don’t feel capable of changing wicks yourself, hardware stores like Headley’s will do it for you and it only costs about twenty bucks plus the wick. I know the local guy, A.J., who does these things at Headley’s and he’s very good, but I still do this myself. Replacing wicks, nothing more than that, will give your OR-77 about three years of useful life.
The least important thing to fail will be the electronic lighting system. Actually all that does is lift the wind cover when you push the lighting button on the front, then a very fragile electrode advances to the wick, and the current from the two D-cell batteries is supposed to light the flame. This works for awhile and might last a year. Mine lasted the first winter and failed the second. It’s silly to send for parts and fix this. Get a box of long wooden fireplace matches and some regular kitchen matches. You can use the long matches many times, just light them with the kitchen matches after the first striking. Raise the wick, lift the wind cover, and insert the lit, long wooden match. Presto. Cheap and dependable.
In the fall, when I sense winter pending (obviously, the leaves turn color and fall, uhoh) I get my kerosene heaters out and give them a workover. I don’t just check the wick, I check the well where the wick rides. The first time I did this I found a patch of what looked like corrosion on the back wall of the well and I polished that out with emery cloth. Any corrosion on the wall of the well will cause drag on the wick and affect the wick height, which is very important. A wick set unevenly will not burn evenly. I have not seen any more of this corrosion, which is surprising, but I think it happened because the factory settings shifted the wick holder towards the back of the well. You need to watch that when you put these heaters back together. Make sure the wick is centered. Don’t over-tighten that fixture because that alone will set the wick off to one side. Get it right and leave it that way. When replacing a wick, I have also learned to give the wick some extra height instead of setting the guideline flush with the holder. When I set it flush, the wick is set too short to burn properly. If I see about an eighth of an inch between the guideline and the wick holder, that is usually right. You can turn the wick down, but you can’t turn it up, so give it some extra height. In the owner’s manuals you’ll find recommended heights in millimeters and it’s good to use that as a reference instead of the mark on the wick. Replacing these wicks is awkward, there are teeth on the wick holder that always want to snag the wrong places, so I have learned that the best way to do this is to flatten the wick and make a C-shape out of it and start there, work from the center out to either side and then open the wick up fully and press the rest of it into place.
Getting the OR-77 beyond the third year is where it gets tricky, and it’s actually very sensible to just buy a new one then because they don’t cost that much. What becomes a serious issue with this stove is that a safety feature wears out. If you tip this stove, a weight inside the stove trips the spring-loaded mechanism that pulls the wick down and snuffs out the fire. That’s very important in case you knock the stove over, because then the stove probably won’t light the spreading pool of kerosene on fire on your floor. I doubt this is guaranteed to not happen but it’s a good idea to have this feature. The best safety feature is not to knock the stove over, period. A geared wheel and a toggle bar are the main parts of this safety system, and after about three years the teeth of that wheel will wear down, because it’s not hardened steel. That makes the safety shutoff very touchy. I got through another year without tinkering with this but I had to walk very softly around the stove or my footsteps would trigger it and it would shut itself off.
So, you could try to order replacement parts from the company, but I haven’t. Here’s the link for the parts manual for the OR-77 and good luck with that. Seems unlikely that I would get the right parts or that it would be economical. I will need to buy a new stove someday anyway. This kind of thing does bother me, however, because I have the Old Alaskan Trapper mentality and I’m compelled to find a way to keep things going, just in case I’m in a situation where I can’t get either parts or a new stove.
On the OR-77, it’s easy. All you need is one of those fireplace matches or something of similar size, and a pocket knife. The flame adjustment knob on this stove is only a friction fit, so you can pull it out a little on the shaft. Turn it to maximum position and lay the fireplace match behind it, then press it back against the match. Mark the spots where the match lies, an ink pen will do this.
Now pull the knob off and with your pocket knife, carve two notches within those two sets of marks. Make them square so the match fits neatly, and make them almost as deep as the width of the fireplace match.
To set your wick, pull the knob out slightly on the shaft and lay the match (it’s about eight inches long) behind the knob. Press the knob in until the match is seated in those notches. You can still adjust flame height by sliding the match in and out, but this will defeat that safety feature where the flame hopefully goes out if you somehow knock the stove over. This is still a good thing to know, if the kerosene heater is your only heat, and you are on a tight budget or you live out in the wilderness in Alaska and don’t have the sense to make a fireplace or haul in a wood stove.