My home generator will turn over but will not start-check for fire to the plugs and it has it check the NG line to the back of it and it has gas
Which brand/model generator? Having thatÂ information always helps.
When it turns over but doesn't start, there could be a problem with either ignition or the fuel delivery.
Did you check the voltage on the spark plug with a neon bulb tester or did you take them out and verify they're clean and not worn out? You may need to clean the plugs and/or restore the electrode gap or just get new NG-rated spark plugs. The gap is different for different size engines, so pay attention to the gap size. This has to be done every 2 years or 200 hours of operation regardless of the engine failures.
There's talk of a new type, star-shaped electrode spark plugs designed for better ignition in natural gas engines. I haven't seen/used those yet, but it sounds like something worth trying if you need new plugs anyhow. Well, novel type plugs or traditional, they still need to be NG rated, so be careful ordering replacements.
As far as fuel mix delivery, not sure to which point you could verify presence of the gas but there are a few potential trouble spots in there:
1. The fuel solenoid may be defective or disconnected from the control board
2. The choke, also electronically controlled, may not be operating properly (plates stuck for example) or disconnected from the control board
In addition to fuel and ignition, valves out of adjustment may also prevent the engine from starting. The valve lash would have to be reset. The proper clearance is 0.002" - 0.004" (0.05-0.1mm)