This image may explain things a bit more. Once again sorry for the terrible picture. Working on improving it. Jeff
I did a few gentle taps. and made three indents at 10 o'clock 2, and 6 o'clock. I did use a flat screwdriver. Though that is the wrong use for that tool. Jeff
The part of the shaft that the o ring slides on is tapered, isn't it? Larger on the seal and smaller on the intake/indent side, right?
Thanks Jeff, I understand the method now. I hope you find a camera that you'll be satisfied with. Jim
I got lazy and didn't want to fire the forge to make a punch so I resorted to the abuse of a flat-blade screw driver, too. Seemed to work fine, the pump does work, albeit at a somewhat low output. It does pressurize the tank. I discovered that the long nipple on the inside of the tank cap can come loose and this will prevent the tank from pressurizing. I snugged it up hand tight and everything worked. I have not re-adjusted the cleaning pin yet and this may prove to be the real root cause. My additional pressurizing only took 30 seconds off the time to boil 2 cups of room temp water, from 6 minutes to 5.5 minutes. However, the flame was much higher and the flame spreader actually got to a dull red (observed in daylight). Over all, I am encouraged.
Upon my second look at the pump, it apparently does not function quite like it should. It still pulls a vacuum on the up-stroke. I will address the cleaning pin next.
I used petroleum jelly and seems to work a bit, have to hold the pump up for a second for the air to get throught before pushing it down. Havent dinged the pump yet at this time. Ron
I reset the cleaning pin as recommended and soaked the parts in a carb cleaner; they were BLACK. After cleaning, and a minute to heat up, it brought 2 cups of water to a boil in 5min 20sec. Probably as good as it gets at sea level. I think I may pound the dents back out of the pump as it seems to leak more on the down stroke now than before. This is not a display unit and I think it works OK for heating noodles and coffee. Probably won't tackle a turkey dinner with it....
I am sorry to hear you pump isn't working sparky. The indents should not be a problem on the down stroke. How much of a indent did you do? Jeff
Tried to make it as close to the pictures as possible. I may pound them back just a bit to see if that helps. The problem is that it does not draw air on the upstroke when connected to the tank. It pulls air/vapor out of the tank. I put my finger over the hole and pulled the knob and it sucked tightly to my finger like an old venom extractor. At the same time, it did not do a good job of pressurizing the tank. As a comparison, I set up my Svea 123 and it boiled the same 2 cups in exactly 4 minutes. This is a close ratio with the rated BTU output of the two stoves. The pot is an aluminum cup with no lid and I am sure a lid would improve the times, too.
Humm Interesting. I don't know why mine works then. If all is working well it should draw air from the top of the pump near the knob. Not the tank. I wonder if it has something to do with my pump cap. I am sorry it didn't work for you.
No problem, we all learned something. I may make the indents a bit deeper but not today. I must remember this little stove is not a Pratt and Whitney JT9D. I just need to slow down and enjoy what it does best.
Last Chapter: I flattened out the indents and there is really no change in performance. However, being that this is a MIDI pump, one stroke is enough to boost the pressure to a high combustion level. For a reality check, I put two cups on our gas range and it took 3:45 to boil it in a thick aluminum pot. 4:30 is not bad for a little brass stove at sea level. The paint job is next. Note of caution: DO NOT use the 1200F high heat BBQ paint. It is soft and does not resist gasoline worth a darn.
PS - I found that Ace Hardware (USA) carries a pale blue paint that is very close to the original Optimus blue. It is the "hammered" texture that gives it a slightly metallic finish. Not perfect but close. About $9.00 US.
I received an email from Pack Stoves (A&H) suggesting that to solve the problem of pulling a vacuum on the backstroke, I take the pump apart, remove the teflon tape from the plunger and re-assemble it. My pump had no teflon tape on it. Anyone else have tape?
