1998 Towlite Water heater Atwood 91601 help needed...

Here is the photo of the thermostat... That lever behind it ,I believe, is the adjustment for the temperature setting... As you can see it is not labeled in any way.
I need to know where to have it positioned for "medium hot" water...
The pilot light is lit and I can put that lever to the "center" position and the heater kicks on. But I need to know where to position that lever so that it will shut down the heater once the water gets medium hot.
If I put the lever all the way to the left the heater stays on and when I put it to the right of that center marking, it goes off..
I had it to the full left position and waited like 20 min and the heater kept on going... How long do I have to wait for the heater to automatically shut off? Or is the full left position always on? (Seems like a waste of propane tho.)
Please help.
It's an Atwood 91601 thermostat... The 91602 (never version) does not use a lever...
I have looked at the manual online for it, but it's all illustrations and not actual pictures. If I had a picture of it to see there might be some markings that show what the level positions are.

I found this and it shows the handle you talk about

https://myrvworks.com/wp-content/uploads/2019/04/Atwood-Water-Heater-Service-Manual.pdf

MAIN BURNER OPERATION
• Gas Control supplies gas to main burner when control knob is set to “ON” position and the
temperature lever is set to desired temperature after pilot is lit.


• Main Burner Orifice meters gas through burner tube.


• Main Burner pilot ignites gas when it reaches end of this tube. Flame height adjusted by sliding air
shutter. Ideal setting is 1/4 way open (.20˝). Flame should be primarily blue with
a trace of yellow.


• Temperature Knob setting of knob determines burner cycle and water temperature. Temperature range is
70°F - 140°F.

Pilot Adjustment
Only the gas pressure, gas valve and the pilot orifice regulate the height of the pilot flame. Early model gas
controls have a pilot adjustment screw, but this screw has very little effect on the pilot. The pilot
adjustment has been removed from the current White Rodger control. The flame should be high enough to
engulf the thermocouple at all times. A pilot flame any larger could blow the E.C.O. in the gas control. This
is typically the result of enlarging the pilot orifice hole with a pin or similar item. For further corrective
measures, refer to the trouble-shooting guide.
Main Burner Adjustment
The gas pressure, air shutter cleanliness of the burner tube and orifice regulate the main burner flame. The
main burner flame should be mainly blue with a trace of yellow and fairly quiet. If it is not, adjust the gas
pressure to 11˝ W.C., ensure that the main burner air shutter is 1/4 way open and verify that the main
burner flame spreader is square to the end of the main burner. For further corrective measures, refer to the
trouble-shooting guide.
Main Burner Alignment
The manifold and main burner should be as perfectly aligned as possible. In other words, the gas valve
should be rotated at the same angle as the main burner tube. If it is not, rotate the gas control and/or the
orifice holder so that the orifice disperses gas straight down the center of the burner tube. If the valve must
be backed off any, check for water leaks at the coupling the control screws into before you operate the
water heater.
Pilot Flame
Thermocouple
On/Off Pilot Knob
Air Shutter
Temperature Lever
Flame Spreader
Burner Tube
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