I was recently plagued by a slow/weak burner on my otherwise fine Gas stove. This unit has sealed gas burners that are near impossible to remove. The most common cause of a weak gas burner is a plugged orifice where the gas enters the burner. This can be caused by a severe boil-over, cleaners or other gunk getting into the burners. The end result is the burner won’t start or has a very weak flame.
To remedy this problem the burner grate and cap are removed. Using a flashlight inspect the orifice for any debris or buildup on the surface. Use a swab to clean this off. Then using and appropriately sized piece of stiff wire or “Tip Cleaner” plunge it into the orifice several times to remove any internal debris. If you use a tip cleaner make sure you do not force it in and it doesn’t enlarge the existing hole. For my Natural Gas stove I used the second largest one with success.
After cleaning return the burner cap and grate to the original position and test the burner. You may see some colors coming out of the burner (like green) from some small bits of brass that may have been removed but the burner should return to normal pretty quickly. If it doesn’t you may want to contact a service technician.