Where do I even begin to locate a serial number? I have a Yale that fits this exact description I purchased in 1995. All I was told was it had a newly remanned Mazda engine that was OEM. I think the "brain box" might be bad as I am not getting any spark. I replaced coil which did not help. It has always ran very well for the most part and hadn't been ran in over a year. Trying to figure out what this box is called to even order one.