Soft serve machine is making it to soft to serve
We have a little shop in a tourist town and have been having problems with our stoelting soft serve machine. We bought the machine used a few years ago and was much better than our older machine. But we are finding that it just isn't doing what we want now that we want to do more with our ice cream. When we have the machine set to keep it frozen during the day after the initial cooling cycle finishes the ice cream is really nice and firm, but if it is left alone for a while (still set on the automatic freeze) it is getting softer. This year we had starting using cone dip and most of the icecreams are falling into the dip because it isn't cold enough. We also use a flavour addition out of the machine and after it has been mixed, many times the icecream is so soft it's a melted puddle when it's handed to the customer.
We have had our machine checked by a refridgeration guy and he says it doesn't need any coolant. He also cleaned all the built up dust out of the inside for us and it seemed to help a little at first. We have gone through the manual and can't find anything. We have talked with Stoelting directly and have reset all the codes and it hasn't made a big difference. We have adjusted the little turning thing to make it colder to the coldest and it still isn't firm enough.
What else could the problem be? Would using a different soft serve mix make a difference? What temperature should the ice cream be after it comes out of the machine?