Remove the line going from the shutterstat to the fan, Get the engine up to 210 or so on the gauge, use an air compressor and air blower attachment put to the line, if the fan runs, it's either the shutterstat or one of the elbows is clogged up..Or as Suprman said hook both airlines together to rule out fanclutch ect... An elbow with 1/4" flares or 1/4 inch t with cap
http://www.steelsoldiers.com/showth...e-shutterstat-fails-cheap-fix-for-emergencies .... I went and bought a shutterstat because my fan on my 923A2 stopped working. Was about to start swapping them out, pulled the elbows off the old shutterstat and noticed one of the elbows appears to have a filter in it, looked completely clogged up. Bought an elbow, tada..... Not the shutterstat.