May want to test the thermistor after you free it from the evil probe and before you capture it in the refrigerator....


"Bob Hoover" wrote in message ...
Ray Toews wrote in message ...
Thanks for the insightful help, I planned to install some sensors to
check the rise. I think I will glue one rite to the outside of the
carb at the intake for as realistic a measurment as possible.
I use those little automotive outside air temp sensors I buy from
Canadian Tire,

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Dear Ray (and the Group),

Take your outside air temp sensor and hit it with a hammer. Okay,
okay... squeeze it with a pair of pliers. IF (Big IF) IF... you're
lucky, inside you will find a thermistor about the size of a grain of
sand; the the tiny bit of **** that seems to be welded to the wires.

To measure temperature at the carb, drill a hole in it large enough to
accept the thermistor. (#80 works for the little thermistors.) SOP
is one hole just above the throttle plate (if you have a throttle
plate). (If you want to measure inlet air, put a thermistor on the
carb-side of your carb heat box.) Now put a piece of tape over the
hole on the INSIDE of the carb and go find yourself some metal-filled
epoxy. The Good Stuff comes from Kodak, contains silver and transfers
heat with virtually no loss at all. Mix up a dot of it, dip the
thermistor into the epoxy and plug it into the hole. Now let it cure.
(Don't forget to remove the tape.)

You may install a suitable connector, if you wish. Should I mention
that it's a good idea to only drill where the carb is solid metal?
(Nah!)

A carburetor makes a nice refrigerator. Outside air temp has
surprisingly little to do with it. The pressure drop across the
venturi (traditional carb assumed) and gasoline's endothermic
change-of-state is enough to put frost on a can of beer quick like a
bunny. With a suitable temperature probe in place you can sit there
warm & cozy in the cockpit and see it all happen long before the
engine starts running ruff and the Bad Silence ensues. (You may want
to pull out that red knob over there...)

-R.S.Hoover