Optimus stove repair

[Joe500]

I have an Optimus International Series 6000 gas stove on my boat. I think this is the original stove that came with the boat 30 years ago and this manufacturer no longer seems to exist. The left burner no longer stays lit. I press the knob in, light the burner with a match, and then wait for the thermocouples to warm up, but it never does. Once I stop pushing the knob in, the left burner goes out.

The right burner and stove work fine. Last winter I repaired the oven knob as it had some gook in it and wouldn’t turn. I removed also the left burner knob at the time to study how the knob is supposed to turn. So, it’s possible I did something wrong when I reinstalled it, but I’m also suspecting that the left thermocoupler is broken or loose.

I don’t know how to remove the thermocoupler or what else might be easily removable here. Are there any stove manufacturers that use similar thermocouplers that I could order a replacement? Anything else to check?

Any advice would be appreciated. I’m including some photos.