The '83 I just bought has a new Seaward Hillerange propane stove which previous owners never used. I turned on the tank in the aft lazerette, switched on the solenoid, turned the burner knob to IGN, held it in for 10 seconds per instructions, then pushed in the red ignitor on the left of the front panel. A flame sparked but no ignition; no ignition on either burner. Any suggestions why the stove won't light? Thanks in advance