Okeefe and Merritt oven won't light, pilot light very low and not adjustable

[Jaime Nahman]

Have an Okeefe & Merritt Model 55-280-5. It had been working fine. Now pilot is very low (a change) and the adjustment screw under the griddle does not change the pilot height. Main gas valve does not come on so oven cannot be manually lit. Any suggestions appreciated.