Gordon
If you are using 75. That means you're using less propane.
The lower the parameter the more propane, the higher the # the less propane.

I set mine so when it fires up there is very little or no fire at all.

Temperature plays a part in this. If the parameter is set for a 60 degree day, and then you start your engine on a 90 degree day the propane preesure is greater and you'll have a little more flame.
Mine happens to start perfectly at 55.

Scott