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Posted: Wed Oct 13, 2021 10:26 pm
I recently picked up a Coleman 413G two burner stove. The stove was in quite good shape and appeared to have only been used once or twice. There was some not quite solidified grease inside the case so I pulled the manifold and drip tray out. Manifold was thoroughly cleaned with water,compressed air and a flexible bottle brush then inspected with a flexible endoscope. The inside of the bunsen and manifold is completely clean.
The generator was disassembled, cleaned and reassembled. The tip is tight.
When I fire the stove, with light lever up, I get lots of yellow flame even after 3-4 minutes with lever up or down.
Obviously way too rich. If I open the secondary burner the flame on the primary drops into a nice blue flame at all settings from simmer to full open.
I have moved this tank to another 413G and that stove works as it should. I have taken the tank from the other stove and put it on this stove and the problem is the same. That means it's not in the tank. Normally I would think it is an obstructed bunsen or manifold, but I know there is nothing in there.
At this point any ideas will be entertained.
Posted: Wed Oct 13, 2021 10:34 pm
"At this point any ideas will be entertained."
When just using the primary burner, have you tried throttling back the fuel control valve to reduce the fuel flow to the burner?
Posted: Wed Oct 13, 2021 11:00 pm
Okay it's been awhile since I've worked on one of these, but I seem to recall seeing an air restrictor on the auxillary burner... Possible it could've been swapped from side to side? I may be thinking something else
Posted: Wed Oct 13, 2021 11:08 pm
Restrictor is where it should be. Behavior starts at 1/4 turn of the valve. Even at a simmer setting it's running yellow.
Posted: Wed Oct 13, 2021 11:13 pm
Does moving the gen out of the mixing chamber a tad make any difference? Obviously this is a risky test. Make sure not to pull the gen too far outward.
Posted: Thu Oct 14, 2021 12:26 am
>>Make sure not to pull the gen too far outward.
What could go wrong?
Posted: Thu Oct 14, 2021 12:30 am
Did you happen to put the aux burner on the primary side? If memory serves, they are different. ...just a shot in the dark
Posted: Thu Oct 14, 2021 12:50 am
Burners are in the correct position. Yes I did try moving the tip of the generator closer to the mouth of the bunsen and it improved some but not to what it should be.
Posted: Thu Oct 14, 2021 12:52 am
FWIW the tip goes just as far into the bunsen on the other 413 and it work like its supposed to.
Posted: Thu Oct 14, 2021 1:08 am
Possibly the burner rings are stacked wrong.
Posted: Thu Oct 14, 2021 1:14 am
I have two 413s disassembled out in the shed. One is a D, the other is a G. The air hole in the bottom of the D's mixing chamber is 3/4 inch in diameter. The air hole in the bottom of the G's mixing chamber is 7/8 inch. So, the G's air hole is 36% larger than the D's. Could it be that your recently-purchased stove ended up with a manifold from an earlier model, and the air hole is too small? Are the holes the same size on your two Gs?
Posted: Thu Oct 14, 2021 1:58 am
"Behavior starts at 1/4 turn of the valve. Even at a simmer setting it's running yellow."
I wouldn't rely too much on valve knob position to evaluate things, I'd just monitor the burner flame for the time being. When you adjust the knob, the fuel controlling mechanism should be valve rod tip interfacing with the generator orifice. I'd fire it back up, let it run for a minute or so to let it stabilize, then tweak the knob to see if there is a good flame sweet spot. As you apparently took a lot of things apart, there could be parts or reassembly issues in play.
Posted: Thu Oct 14, 2021 3:05 am
I think TwoCanoes is on the right track thinking something is amiss with mixing chamber hole. Can try making opening smaller with some tin foil and see if it get worse. enlarging the hole is a one way street. By swapping out founts the only thing left is the manifold/chamber . That is the carburetor for the stove and too small hole is like have the choke on and running rich.
Posted: Thu Oct 14, 2021 3:51 am
Is pretty much normal for main burner to burn too rich till secondary is open, just the way tis designed.
And it is easy to flood these a little bit, and it takes much longer than you would think to burn off the excess. Opening the secondary, again, lets a lot more air flow and the yellow goes away.
corrosion/coating on the burner can cause yellow too. Let it burn a while.
Posted: Thu Oct 14, 2021 11:44 am
As said above, the stove has had very little use. Burner rings are clean, assembled properly. I've let it run for at least 5 minutes to check for possibility of flooding. I agree it acts like a classic manifold or bunsen restriction. I haven't measured the air intakes but they appear to be the same size judging by touch. I've also tried varying tank pressure from 10 to 40 pumps. No real difference until I over pressurize it then it just gets worse, as would be expected.
Posted: Thu Oct 14, 2021 1:37 pm
You could maybe narrow the cause down by swapping the main burners between this stove and the other that works properly. That could tell you whether the issue is with the burner or the bunsen/manifold.
Just spitballin' here.
Posted: Thu Oct 14, 2021 2:29 pm
Already tried swapping burners. No difference.
Posted: Thu Oct 14, 2021 2:48 pm
Cottage_hill_bill wrote: ↑Thu Oct 14, 2021 2:29 pm
Already tried swapping burners. No difference.
My bad, I thought you had swapped the whole stove not just the rings and burner bowl.
Posted: Thu Oct 14, 2021 4:17 pm
"As said above, the stove has had very little use. Burner rings are clean, assembled properly."
Two trouble shooting take aways from that: 1) the stove probably was never taken apart or worked on by a previous owner, and was the way it came from the factory, and 2) you *assume* you assembled the burner parts correctly after taking them apart and working on them and swapping things about. Not saying that is the issue, but is often an error trap in getting things working correctly again. Did you take apart the generator section of the stove? Might be possible some of the throttling capability of the generator orifice valve and the generator orifice as that is probably key for one burner operation.
Posted: Thu Oct 14, 2021 9:20 pm
This afternoon I seem to have found the issue. Apparently this stove wants a lot more pressure than others I've worked with. My normal startup for both lanterns and stoves is 30-35 pumps then add a few pumps after the F/A lever is turned down to replace what's lost with the lever up. Usually about 10-20 extra pumps is enough for things to run just fine. After this one had warmed up for nearly 5 minutes I added about 30-40 pumps (tank was a measured 1/2 full) and it settled down and behaved. I'm letting it cool and will try to repeat the results.
This isn't my first encounter with a Coleman suitcase stove, so I don't assume I assembled the burner correctly, I have put dozens if not hundreds of them together so I know it was assembled correctly. I had also swapped the burner stack complete with another stove. The generator and valve were disassembled and cleaned. As I stated above, the entire tank assembly was hung on another stove where it worked properly, so that rules out issues with the generator. I also used a tank from another stove and it exhibited the same bad behavior.
Posted: Thu Oct 14, 2021 11:57 pm
You are definitely a stovie!
Glad you figured it out
Posted: Mon Oct 18, 2021 10:29 pm
I would run some pipe cleaners in the elbow , very possible you have spider webs or spider egg sacks.