Need help with an AGM KampKook LCS-41 rebuild

I'll try and answer your question(s) regarding the air pump on your KampKook.

The air pump plunger from your Kamplite lantern was designed to be used with a check valve that is a close cousin that Coleman uses. Hence, the tapered tip. And the pump plunger is integral with the stem where Coleman uses two separate pieces(plunger and air stem).

Now, the pump on your right was not designed to go into the check valve and seal it off, per se. The plunger will bottom out and that's it. No locking feature to keep the plunger down. Those threads are there to only remove the hex nut that secures the pump leather and washer and that design was common to AGM dating back to their first instant lighting lanterns and stoves of the 30s. If anything, the knob design changed to your style when it became Kamplite under Queen Stove Works. In fact, Prentiss Wabers used an almost identical pump barrel assembly with their lanterns and stoves. I don't know if they would interchange.

Now, the hex fitting at the bottom of the pump barrel does come off. The threads are probably slightly siezed but it will come off. Inside of that housing is a small, round brass piece, about the size of a pencil eraser that has either a rubber insert or possibly cork. Between that and the bottom of the housing is a small spring that gives the check valve its tension.

That rubber/cork insert wears out or can get so hard as to not seal properly against the bottom of the pump barrel. You can test that by re-assembling the pump assembly, keeping the fuel valve mounted on the tank and shut off, pumping it up with air and dunk the pump portion of the fuel tank underwater. Bubbles indicate a bad seal, obviously.

That insert can be replaced even though there are no current parts available. Some I know cut out a piece of rubber or cork and stuffed it in there after removing the old material but it does take some patience.

Your set-up was not the greatest design by anyone. On paper, it looks impressive. Out in the field, it's one of the weakest features of a stove or lantern using that design, in my opinion. I've had lots of AGM & Prentiss Wabers lanterns and stoves in the past and those are always one of the biggest problems. Doesn't seem to want to pump in much air and frequent pumping does seem to be the order of the day. That's not to say that is normal but it does seem that way.

When Kamplite became Thermos at the end of the 50s into the 60s, Thermos did improve the design where there was a small metal check valve but it is not serviceable other than replacing the O-Ring that they used in lieu of pump leathers. Which is an idea in itself. It is possible that the later Thermos pump assembly just may work in your KampKook but I can't be sure. I know I did just that with an older AGM lantern and the pump assembly functioned perfectly and retained air better than the old design.

That recessed ring you refer to is probably where the bottom, threaded portion was soldered onto the pump barrel at the factory. I think that is the thickest portion of the barrel. Doesn't affect the pumping operation.

 

Thank you Coleman413C
I'll take another crack at removing that check valve and get back to you.

 

Almost a year later and still no luck with that check valve. Christmas preparations came around last year and the stove project sort of lost priority, but alas, winter is here again and with it a renewed interest in previously shelved projects.

I've put everything back together and have two problem areas. When previously removing the valve body, I made the mistake of not noting how many turns it was threaded into the tank. I have threaded it back in as tightly as I thought it should be; I don't think I could get one more turn out of it without stripping something. After pumping it full of only air and testing it under water, it's leaking at a rate of 1 to 2 bubbles every second. I had previously noted that there seems to be no consensus here on the forums about the use of thread sealant, so I opted not to use any. Guess I'll have to try it again with some Teflon tape on it. I know this is a highly subjective question, but just how much force is required to get a tight seal on the threads? When I removed the valve assembly, I had it locked in my vise and turned the tank by hand to loosen everything. The full length of the tank offers quite a bit of leverage. Well, I broke the vise earlier this summer, so I'm now putting the assembly back in using a 15mm open-end wrench that only offers about 6 inches of leverage. I'm still concerned that with the amount of resistance I'm feeling thru the wrench, that I may strip the threads if I try to go for one more turn. I have a tendency to over-tighten things anyway; I did manage to break a vise after all. I guess ideally I'm looking for someone with a foot/lb figure.

The second and bigger problem is that cursed check valve. It's not working and I can't get it loose. Once I've pumped air pressure into the tank the plunger won't stay down due to air escaping thru the check valve. Interestingly, the air doesn't readily get around the leather plunger and leak out around the pump stem; it just pushes the stem all the way out and then very gradually seeps past the plunger at a rate of about one bubble every 15 seconds. It seems that once the tank is full of fuel, however, that I'm going to end up with the pump tube flooded with fuel, and wet hands every time I go to add more air. So after this discovery I became more intent on getting that check valve to budge. Under a ridiculous amount of force it finally moved, but after one full turn it still feels galled. It's now sitting in a PB Blaster / 3-IN-One oil bath, but I don't think it's going to come off without either stripping the threads or snapping off outright. This brings me to the question that many on here will know, but I am clueless about. Assuming the check valve breaks off the end, what is the best way to go about attaching a brass 1/8 NPT female half coupling to the end of the pump tube assembly? Solder, braze? Is it even feasible? With a female thread on the end of the pump tube, I can then screw on a brass miniature check valve like the one I have linked to below at WW Grainger. It seems to me that I can make something positive out of this bad situation by getting around the weakest link of these old AGMs. I would also appreciate any input on the appropriateness of this particular valve.

brass check valve info:
http://www.grainger.com/Grainger/SMC-Spring-Check-Valve-4DHR6

-is 1 PSI cracking pressure greater or less than Coleman check valves
-are Viton seals adequate for sitting in fuel
-is a piston type design as well suited as a ball and cone design
-what are the advantages of a poppet design


Here's another look at the pump tube check valve.
Can I just remove the valve and solder/braze a brass pipe coupler to the thick piece on the end?


By the way, here's a shot of the freshly cleaned manifold running full blast off of the fuel tank from my Coleman 414.
I wonder if I can expect comparable output from the AGM tank?

 

Hello Howecollc,

I have a stove just like yours that had the same two problems you describe above. On the valve to tank seal, I used the red Loctite seal and it worked perfectly.

On the second part about the check valve, I put the end of the pump tube in a vice since it appears pretty solid. The end of the tube has a solid plate that holds up pretty well under the pressure. I couldn't get it loose any other way. I was able to get a pretty tight hold on to it and loosen the large nut on the end of the tube and it broke free. On the face of my vice, I used a piece of aluminum on both sides so that the tube would not be scarred and I put the tube in facing up so that only the nut was exposed. I then pulled out an adjustable wrench/spanner and tightened that down so that it would not slip off. At this point I was able to turn the nut and remove it and get at the check valve.

Turned out the pip was all that needed replacing and the spring needed a little stretching. Had to play with it to get the right tension. Too much tension made it impossible to pump. Not enough tension and it wouldn't seal. Once I got it, it came out working perfectly. It's one of my favorite stoves now. Love the cast iron.

As for the generator, I had the same dilemma as the prior posts show. I decided not to cut the generator to pieces but I was able to get the coil out and clean it after I removed the tip and did a heat and quench on the whole generator. I was able to remove a lot of carbon this way. I don't think I removed very much from the large filter tube, but in the end the stove works quite well after my small efforts with the heat and quench. It may have been just enough to clear the filter tube.

Hope that helps,
sam

 

Many thanks for the info idahostoveguy,

What model AGM stove do you have; is it identical to mine? I wonder why my grandfather would have chosen an AGM over a Coleman, but I imagine it probably had something to do with Sears carrying the brand back then. Most of his hunting/camping stuff came from either Sears mail-order or LL Bean.

Were you saying you used Loctite red threadlocker or red HVAC sealant on the fuel assembly?

I like the aluminum idea to avoid scratches on the pump tube. I’ve used both duct and electrical tape in the past to avoid marring things, but they never provided complete protection to the finish.

Is your generator the type that has the long cylinder on top to facilitate burning leaded gas, and if so, how did you go about removing the “barrier” (pictured earlier in this thread) that resides inside the tube? If yours didn’t have the barrier, did the generator coil run the full length of the gen tube? Mine is only long enough to run from the gas tip to about 2 inches from the back where it meets the “barrier”.

The check valve is still sitting in the penetrating oil; I’ll give another try to loosening it tomorrow.

Once again, thanks for the help,
Jay

 

Hi Jay,

Yes, I meant the Loctite red threadlocker. Good stuff.

Yes again on the cylinder on top. It was another reason why I bought it. It looked unusual.

My generator's coil measures from the tip of the generator tube to the barrier. I'm pretty sure that barrier is welded in. I tried to remove it thinking that it was some part that was lodged in there but it wouldn't budge. Once I got the coil out through heat and quench, I was able to clean the coil more thoroughly and also clean the generator tube with a .22 caliber gun barrel brush. Got it as clean as a whistle.

Like I said before, I did the heat and quench on the cylinder as well. I don't know if that did any good but I got my stove burning really well.

Have a great day!

sam

 

Hello again Sam,

I hate to seem dense, but I'm still not clear on how you got the coil out of the generator. It seems you're saying it came out thru the tip of the gen after removing the gas tip and jet. However, the the hole in the tip of my gen is only a hair over 1/8" in diameter. I can see the coil thru this hole and it looks to be 3/16" to 1/4" around; certainly too large to fit thru the hole. If I were to enlarge this hole the gas tip would then be free to travel back into the gen tube after re-assembly.

Thanks again,
Jay

 

Hi Jay,

No dumb questions on this forum. My gen only had the barrier near the valve end of the generator as opposed to the jet tip end. I managed to get the jet tip off and then found that the generator was clogged with carbon that I couldn't get the coil out at first, but after using a torch on the generator to burn out the carbon that freed up the coil so I could get it out.

So here is what I did:

1. Took the jet tip off.
2. Removed the gen tube from the main valve.
3. Fired up my propane torch. Didn't need a high heat torch, just enough heat is all that is needed.
4. Heated up the gen tube until it started turning red.
5. Dumped it cold water.
6. Repeated steps 4 and 5 until the coil fell out.
7. Cleaned of the coil.
8. Used .22 caliber gun barrel brush to clean the gen out completely.
9. Reassembled.

This all assumes you don't have another barrier at the jet tip end of the gen tube. I'm thinking that there shouldn't be one, only the single barrier at the other end. But, you never know what you might run into from the old days.

I'm guessing that your coil is just stuck inside with all that carbon. Hopefully it is.

Hope that helps,
sam

 

Can anyone supply a copy of what the complet KampKook pump assembly looks like? I currently have one and believes something is missing on it.