Atwood hot water heater

Clean out the cobwebs in the tube where you see the flame. Compressed air works nicely.

Another possibility is the jet is partly clogged.

I'm sure there are other potential failure points.

When was the last time you serviced the water heater? As above, clean out the burner tube, check the flame for proper burn - blue flame not yellow.

Notified moderators to move post to the correct section.

Done :)

Can you post the model number of your water heater and the rev number?

Do you get a DSI fault on the inside panel when on gas?

A 2002 Atwood heater would have a separate T stat for the electric and the gas burner side. It may be that the gas side T stat is not working correctly. Opens up too soon.

Does the gas burner shut off or run constantly, just the water does not get hot as the electric side does?

How long did the gas burner run from an overnight cool down of the water heater? 20 minutes, 40 minutes, etc

Another thing, on a 2002 Atwood with both gas and electric, the electric side and the gas side both have their own ECO (emergency cut-off) switch. The ECO is supposed to open up in the 180 F range. The gas T stat is supposed to open at 140 F range, and if the gas ECO opens up lower than 140 F as it has a problem, then the water will not get to temp as it is overriding the gas T stat.

Need more info to go on.