As has already been mentioned, carbide lamps have a reputation for being quirky, finicky, and troublesome. This is primarily because they are far more complex than electric lights. A carbide has many more parts, therefore more things can malfunction. There have been a number of troubleshooting guides published in caving publications. However, the most complete guide to carbide lamp troubleshooting has been published in Clemmer's book American Miner's Carbide Lamps. This troubleshooting guide is largely based on Clemmer's with additions and editing from other guides.

No spark from striker assemblyFlint missingReplace
Spring missing Replace
Spark wheel too smooth
Assembly clogged with mud, dirt, wax, etc. Clean
Spring pressure too tight/looseLoosen/tighten spring nut; replace nut if missing
Assembly is damp or wet Dry or replace assembly
Assembly is reversed, throwing spark away from burner tip Loosen assembly nut and reverse striker so spark is directed at burner tip
Bad striking technique Practice or obtain flame from matches, lighter, or other carbide caver
No flame Carbide is exhausted or missing Clean out spent carbide and refill
Water is exhausted or missing Refill water chamber
Gasket is worn or badly cracked Clean gasket seating area and replace (Mud has been used in emergencies as a gasket material, but will dry rapidly, crack, and fall away)
Gasket is not seated properly Invert gasket and rethread lamp bottom
Felt is wet, brittle, dirty, or worn Dry or replace felt (can be removed entirely in an emergency
Cracks or holes in lamp Repair lamp with solder or replace; change bottoms (radiator sealer works poorly here. Mud is not much better.)
Lamp bottom is not seated properly Clean and oil lamp threads. Carefully rethread
Tip is clogged or blocked Clean tip with tip cleaner. To widen orifice, use tip reamer
Gas tube to burner tip is plugged or blocked Remove tip, felt holder, felt, felt plate. Clean out and brush out tube
Water door vent is clogged (This may prevent water from dropping though valve to carbide) Clean
Poor striking technique (assuming there is a spark) Practice. Cup hand over reflector for 15 seconds. Just before striking, open hand slightly, permitting oxygen to mix with acetylene. Strike in a deliberate motion
Water valve is clogged, or broken Increase water flow slowly. If malfunction persists, clean spent carbide from valve end and recheck water flow. Blow through the water tank to clear stubborn debris. Repair/replace water valve/lamp if broken
Water bubbles exiting from tip Soaked felt and gas tube Replace/dry felt. Filter on a cigarette can sponge water out of gas tube to burner tip. (In an emergency these can act as temporary felts.)
Submerged/soaked tip Remove and blow through tip sharply
Flame coming from around gasket/ pockets of gas igniting around lamp Lamp is threaded incorrectly Carefully rethread lamp
Gasket is old, cracked, or brittle Either invert or replace gasket. Clean gasket seating area
Flame coming from water door vent Gas is being blocked from burner tip and being shunted back through water feed into water tank and subsequently ignited Ream burner tip, replace felt, clean foreign debris from gas tube and burner tip.
Sputtering flame Tip is cracked/ misfit Replace tip
Water in burner tip tube, felt is wet Dry out tube, replace felt
Tilted or angled flame Cracked burner tip Replace burner tip
Dirty burner tip Clean or ream
Weak, irregular flame Water supply depleted Refill water supply
Carbide supply depleted Refill lamp bottom with carbide
Burner tip partially plugged Clean, ream, replace burner tip
Wet felt Dry or replace
Cracks in lamp; acetylene escapes and may ignite Repair cracks or replace lamp
Gasket is old, cracked, or missing Clean gasket seating area and invert or replace gasket
Carbide caked on valve stem Loosen lamp bottom, wiggle bottom. Clean and flush valve stem.
Using dirty water Flush water feed valve, replace with clean water
Excessive flame
Too much water being valved into carbide Turn off water valve and wait for excess gas to be vented
Burner tip has been reamed excessively, orifice widened (note very yellow flame) Replace tip
Excessive flame
Sheer force of acetylene venting from burner tip blows out existing flame Cut back water supply; wait for gas to vent
The above situation with a plugged water door vent Unplug vent, cut back water supply. Wait for excess gas to vent.
Excessive flame
(continuous and uncontrollable)
Broken water feed device; wide open water feed Repair valve, valve seat or replace lamp
Bubbling in water tank (often noted in normally functioning lamps) Excess acetylene being shunted through water valve and percolating through water tank Cut back acetylene generation by slowing water feed
Very hot lamp, particularly bottoms Too much acetylene being generated Slow water feed to carbide
Missing cool-grip/ bumper grip Replace
Good flame but poor illumination Dirty reflector Clean with toothbrush and brass cleaner, etc.
Cave character Use brighter light if cave walls, ceiling, etc. are colored unusually dark

Clemmer, Gregg S. American Miner's Carbide Lamps, pp. 115-116. Used by permission.

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