I was searching for something else and came upon this post by SHO NUT speaking about the cooling system. Basically, he explains that without a thermostat the SHO will overheat...
Careful guys, the SHO cooling system is unlike anything seen in most domestic engines. It uses a full flow recirculation system (that's what the coolant tube is used for on the top of the engine) to recirculate all the coolant around the rad when it's not being used, as opposed to the t-stat just shutting the coolant flow off like most other engines do. That's why a 'normal' thermostat won't work in an SHO. The SHO thermostat is actually a 3-way diverter valve, as opposed to an on/off valve, either directing the flow through the tube, through the rad, or a combination of both, depending on the engine's cooling needs, all the while maintaining a full coolant flow through the block/heads (a good idea). If the diverter section (the disc on the back end of the t-stat) isn't part of the thermostat, then the water flow will go though the tube instead of the rad (just like if you remove the t-stat), and the engine will overheat, regardless of whether or not the t-stat is open or closed.
Just a bit of insight for you. You need to first put the thermostat back in.
Doug
