I just picked up one of these sealed in the shipping carton. These engines are well over 10 years old and anytime I pickup an engine like this I like to do a good service on it. My problem is I can’t figure out how to get the boiler off . I’ve removed every screw I can find and this thing is locked down. Anyone ever had one of these open for service? I know they’re aren’t a ton of these out there but surely someone’s had one apart. What am I missing?