[T2] conceivable blunder

[Robert Mann]

Chris
          Is it possible that your thermocouples (acting as spark plug washers, in the normal arrangement) could be of the wrong type so as to read way high?  AFAIK two types have been used in such applications.  My aero-engine thermometer came with a Type J to go under the spark plug (and a Type J meat thermometer substituting for the dipstick, reading oil T by a DPDT switch at the guage).  I never see readings nearly as high as you quote.  I think the other thermocouple type is designated K.  Could an accidental switcherootie have hit you?
         I readily admit I don’t know whether a K thermocouple would read higher, as opposed to lower, than a J.  

RM