Stove burner not lighting despite spark ?

There is normally a small channel from the centre of the burner leading towards the spark gap. If the burner has become rotated from the correct position or the channel is partially blocked it can lead to the symptoms you describe. I spent ages trying to get a hob working in a place I rent out and that turned out to be the cause - found it on a youtube video.

Good Luck Bob

Position of the spark re the gas?

Oxygen not mixing with the gas at the point where the spark is? Brian

Thanks for that. Just removed it, checked it all over - can see the tiny "notch" which acts as you describe (the body can't be mislocated - it's only got one fitting).

Sadly no go :(

Spark is a bright and good as for all the other burners.

I opened up mine a bit with a small file for "instant" lighting.

The first clue I had about the problem was that it would light if I blew gently onto the burner whilst pressing the igniter.

If so, there's something very subtle about it ...

You may have knocked the spark contacts a little out of position.

Mike

It was my first thought, but looking down at them, they all seem to spark equally brightly and to the same spot ....

I used to have this when I had a gas cooker. All four "sparking plugs" seemed to have identical sparks after I'd cleaned the burner area, but one refused to light. Leaving it overnight solved it. I can only think that one of the sparks wasn't as hot as the others (because of leakage through moisture) even though it looked the same.

By the way, don't ever put your finger near those contacts when you press the ignition button. It's a very high voltage. One of my neighbours did it by accident and got a very nasty "snakebite" burn.

Jethro_uk brought next idea :

I had a different problem, so no help at all, but...

All four would ignite, but then one, then a second, then the third would eventually refuse to remain lit once ignited. I traced that to what must have been thermocouples having poor connections, to the gas valves. They all seemed tight enough, but must have suffered some oxidation at the terminations of the thermocouples. Loosening then retightening fixed them all. It has been absolutely fine ever since then.

Dunno really. But when I cleaned our hob with loads of Mr Muscle and loads of water one burner would not light up. Out of desperation I blasted it with a hair dryer. This worked. I no longer use loads of Mr Muscle and loads water.

A tiny bit of burnt on food residue can effectively semi block the slot enough. I've had to resort to a brass wire brush in the past to clean out this area.

Good advice. I've not done it, but can easily see how it could happen ...

The spark electrode wears down over time. When it wears too far it gets hard to light the flame. One workaround is to turn the gas to full and immediately down, that creates a larger gas/air cloud & it lights.

NT

I've had this - possibly a drop of water is blocking one of the gas channels?

Give it a good hard blow out or try again after running it hot for a bit.

I've found the same. The smallest water droplet apparently on any part of the burner (usually internal, obviously) seems to stop them lighting, Water in the venturi housing round the jet seems to do the same.

Cheers for all replies.

Tried again this morning - still no joy. Fired it up and let it burn while boiling a kettle :) and whatever the problem was, it's fixed it !!!

I hate cleaning the hob !

Definitely a drop of water clogging a jet or messing up the ignition electrode :)

Probably not this, but when we take the burners off the hob to clean everything then sometimes they won't light (or are very reluctant).

I find that if you wiggle the burner a bit (with a grinding sound between the burner and the seat) then it will light right away.

The spark is clicking away; I am guessing that there is a poor earth through the burner assembly which reduces the efficiency of the spark.

Cheers

Dave R

Very unlikely when there must be some 3 to 5 KV of spark voltage involved. The 2 or 3 thou' of corroded surface layer might look like an insulator to on ohm meter or a 12 volt supply trying to pass 180mA to a