First time poster, long time reader. I have a new (<1 year) 3000000923 (the "Coleman Premium Dual Fuel" lantern, not the Powerhouse, that I purchased new from the local outfitter -- the box does say "288A" on the bottom, but their website says 3000000923) that requires frequent pumping to stay lit and burning bright. I've looked through other posts here and found some helpful information, but even after trying various things suggested in those posts the issue persists.
It's only ever used CF, also newly-purchased from the same outfitter (who goes through stock pretty quick, so it hasn't been sitting around on a shelf for ages), never gasoline. The fuel has always been poured through the filter funnel that came with the lantern, and which is kept in the plastic bag when not being used so as to keep off dust.
When I follow the directions to light it (pump 30 times, hold a flame near the mantles, turn on valve fully) it lights normally as expected. It flares a bit, again as expected, for the first minute or so until the generator heats up, after which it has the usual sound and bright light.
However, it will start pulsing (see video below) after a few minutes. Additional pumping can sometimes reduce the pulsing, but it never really produces a "steady" or even "mostly steady" light.
Additionally, it requires frequent pumping to stay lit. With a full fount (filled to the point where fuel stops going in with the filter funnel, as mentioned in the instruction; it's probably a centimeter or so below the fuel filler opening) and the valve set on full brightness after 15-20 minutes it produces the same amount of light as if it were fully pumped and set to low brightness. An additional 10-20 pumps get it burning back at full brightness again for another 15-20 minutes. Once the fuel level is a bit lower in the fount, it can go about an hour to an hour and fifteen minutes between pumping before getting low enough that the flames go out.
Here's the things I've tried to fix it, all to no effect:
- Turn the valve from high to off several times to have the tip cleaner clean the generator orifice.
- Remove the generator, remove the tip and inspect it. The orifice is clean, and the tip cleaner is not broken.
- Spray the inside of the generator with a copious amount of carb cleaner. (I have not disassembled the generator yet.)
- Replace the generator (thanks OCP!), note that didn't fix it, then do the same things as above, again to no effect. Fuel sprays from the generator tip in the normal way, with nothing strange about the spray pattern.
- Make sure the packing nut on the valve is snug.
- Check and replace the fuel filler cap gasket. No leaks.
- Check to make sure the pump cup is intact and clean (it is, and the problem occurs with both the original neoprene cup and the replacement leather one I put in).
- Verify the check valve does not leak (no leaks).
- Verify the pump pressurizes the fount (it does).
- Remove the valve from the fount and examine the F/A tube. It appears to be in good working order, with the fuel hole clean and free-flowing. The Schrader valve is in good shape.
- Replace the F/A tube. (Thanks OCP!)
- Reassemble everything and check for leaks (none found) with soapy water spray.
- Make sure the air tube for the burner assembly is free of obstructions and aligned with the hole in the (not sure about the name) metal base plate under the heat shield (it's the part that's held down by the u-clip and nut).
If the lantern is turned off and pumped up, it holds pressure indefinitely (weeks and weeks), but rapidly loses pressure and pulses when turned on and running.
Any ideas as to what might be causing this issue, and how I might fix it? I know I'm out of ideas when propane seems more appealing and less problematic!
Thanks in advance!