Some times you can use a fine emery paper to sand the tip of the sparker to get it to work. If some burners work and others don't this can sometimes fix it. Check the docs on your stove as this is listed in mine from 1989.
Personally, I just bought a long extended lighter and don't both any more. Lighting
the stove is not that big a deal but you can fix the starter. I do like the force 10 stoves. The last boat had a thermostat and the other one only has a temperature gage, but they both work great after almost 20 years service
. Owning two is the only problem I have right now. Not so much two stoves but two boats they reside in.