Just got one of these myself and trying to sort it out so it can run. I read that the compounding valve is rubbish and many converted them to simple operation at the expense of having to run a higher gas setting and using more water. One gentleman upgraded his with different cylinders with drain cocks and a drum style compounding valve. I am going to assume the disc style valve on these is kind of like a Mamod reversing valve in its issues, steam leaks from a less than flat sealing surface. Other than some leaking silicone rubber lines that I need to replace, mine does have a bad leak from that valve when its shift one direction, when I shift it the other way, the front engine comes alive but the rear does not. Flip it the other way and the rear starts to come alive, but then the massive steam leak happens.