Concerning Yanmar 2QM and Thermostart. The QM series were only built for two years, if I recall correctly. The design included pre-combustion chambers and relatively low compression. Pre-combustion chamber engines usually have glow plugs, but not the QM's. I am speculating that Yanmar quickly abandoned the QM because of this design issue. Hard cold (initial) start seems to be a chronic problem with this engine. Once warmed up it starts immediately for the rest of the day. As for wiring, connect to the existing start button feed. In practice, you will only press one button at a time; first, the Thermostart for 20 seconds, and then the start button. On mine I purchased a start button from Yanmar for the Thermostart. A single No. 10 wire to the Thermostart terminal completes the wiring. It is grounded to the engine block by way of screwing the body into the dedicated port on the intake manifold. Another necessary modification on this engine is to re-route the diesel return line back to the fuel tank and not to the fuel filter housing. On the way back, you can use this line to keep the thermostart reservoir full. With the return line, as originally designed, going to the fuel filter, you will likely experience air in the fuel line from time to time, necessitating bleeding at the worst possible time.
