I have a chest cooler and it does not keep the 35degrees needed it is alway on 40 degress. is there an adjusting know in the unit?

no rule of thumb
maybe if you got a different thermostat that has a lower setting than standard
however as upright freezers are very bad freezers compared to chest type freezers the lowest reading will be around the -35 degrees C
Why very bad -- every time you open the door you dump 20 degrees out onto the floor and the temp difference is more pronounced than opening the lid of a chest unit which keeps all of the cold in the unit
remember the colder the setting the more the compressor is working

The numbers are generic and don't mean a thing. They are there to make you feel like you have control. Anything under 1 should be very much frozen. If it is not then you have T-stat problem and should address that. Chest freezers run at -25f on average if the freezer has enough product in it. The more food in the freezer the better and more efficiently it will run.

Is your circulating fan working?
Sometimes they stick and need a shot of WD 40 and then work
it back and forth a little until it wants to take off again. Keep me informed
and PLEASE give a Thumbs Up for the effort. The Raz Shack

If this unit has a control it would be located on the outer left side in the lower right hand corner. There would be a dial, the higher the number the cooler the temperature. Many of these chest freezers did not have an adjustable control.

Is your circulating fan working?
Sometimes they stick and need a shot of WD 40 and then work
it back and forth a little until it wants to take off again. Keep me informed
and PLEASE give a Thumbs Up for the effort. The Raz Shack

well one thing to know if the thermostat is working and if the gas is really enough to allow the unit run well.

Is your circulating fan working?
Sometimes they stick and need a shot of WD 40 and then work
it back and forth a little until it wants to take off again. Keep me informed
and PLEASE give a Thumbs Up for the effort. The Raz Shack

Is your circulating fan working?
Sometimes they stick and need a shot of WD 40 and then work
it back and forth a little until it wants to take off again. Keep me informed
and PLEASE give a Thumbs Up for the effort. The Raz Shack

chest freezer operation is among the simplest available. if the compressor is running and its not cooling there are only 2 possibilities. low or no refrigerant and or a bad compressor. so if you have the ability to return the unit I would. could luck peyton

the amount of coolant is not the issue, its strictly a thermostat issue,WOW -40 though i dont know where youd geta thermo to go that low. def not in ANY residential/local appliance outlet