I played a Sweden game up into about 1870. Sweden is easy to industrialize, and has a pretty small population. All my factories were profitable, some highly. I had an army of about 25 brigades.
So why does my economy tank when I turn up military maintenance to full? Even extracting the maximum tax I could, with tariffs, and cutting education pay, I was losing hundreds per day. One brief war and I was absurdly in debt, risking the entire game crashing around me. If it matters, my factories included all the important military goods -- canned food, small arms, ammunition, liquor, etc.
Is this supposed to be like this? This Swedish game should have been perfect conditions -- small army, rich country, tiny navy. If Sweden can't pay to supply its army, who can?
The entire point is that you're supposed to only raise military maintenance to full when you are about to go into war. If you want to be a wuss and have enough money to do whatever you want, cheat. Otherwise if you can't balance the budget with a civilized country, then you need to find a new game.