Hi everyone, I've been working on a Coleman 550 B stove. Troubleshooting was a bit annoying, as one defect was compensating another. It looked like it was a running on a nearly empty tank. Only fumes and air passing through. When shook, it picked up fuel and was burning on for several seconds. But the tank was full. Problem was the outer tube (I don't know, if there is an official part name for that) of the fuel pick up was clogged at the bottom and had a small crack at the top. So it only picked up fumes and no gas. Now about repairing it: First option would be to remove the outer cracked tube. So the inner tube will pick up fuel at the bottom. Risks I'm thinking about: the diameter of the inner tube is not restricted anymore. This could lead to increase of power or irregular combustion. On the other hand, small particles might get picked up and clog the valve/generator. I'm okay with both. But I'm quite unsure if the outer tube serves another purpose: Maybe some kind of protection against the flame burning through the generator and back into the tank. This could only happen, if you're running on fumes and low/no pressure. That's what I would like to avoid. I guess Coleman wouldn't implement this part, if it wasn't necessary. Second option would be to solder the crack. But I'm unsure if this will work out, as it needs to be airtight. Any opinions to this? Or anybody experienced this before? Attached are some images. Thank you very much, Jake
I believe you change the startup procedure, just guessing. Would need to use a torch to preheat the generator quite a bit or likely the stove would never settle down to a blue flame. Duane
The outer tube only carries air from the top of the tank to the pickup inlet for atomization for instant lighting. The early models came with an entire separate valve, generator, and fuel pickup assembly for kerosene/paraffin with no outer tube or pickup orifice fuel restrictor rod/wire. If memory serves, this kero assembly fuel pickup tube was slightly longer than the inner tube on gasoline assembly since the fuel pickup didn't have the additional effective length of the outer tube's pickup orifice. But don't quote me on that. Next time I'm at the shop, I'll dig one out and measure it. You can delete the outer tube, no problem, but you will want to preheat as Duane said. Turning the valve on will instantly flood the generator if you don't. The unrestricted fuel pickup is not a flow issue. Fuel flow to the stove is solely regulated by the gas tip diameter and the cleaning/regulating wire at the far end of the generator. If you don't extend the pickup tube, you won't get as much run as you will have fuel in the tank that the pickup can no longer reach without the outer tube. But the bonus is, you won't have to add additional air NEARLY as much. Hobby stores carry brass tubing that you can use to solder an extension on fairly easily. Or you can just live with with that "maybe 1/8 inch" of unusable fuel. I don't have access to my parts right now, so I can't give you an accurate measurement. There won't be any additional safety concerns. Flames cannot travel back into the generator, through the valve, down the pickup tube into the tank. One of my favorite features of this stove is how fast it is ready to cook after lighting with gasoline/white gas. Deleting the outer tube will no longer allow for instant lighting. All that said, where is the crack and how bad is it. That tube is designed to leak air at the top. It may not be an issue at all. But it shouldn't be difficult to repair if you know how to solder.
Duane is spot on, BTW I initially had this at the top of my post and accidentally didn't copy the top line when I was editing it. When I pasted it back, I didn't catch it. When I did, it was too late to re-edit. My apologies.
