Installation manual

GEM INSTALLATION MANUAL DOCUMENT No. 070906 REV. 1.3
INSIGHT
INSTRUMENT CORP. 11 BOX 122, FORT ERIE, ONTARIO, L2A 5M6
CHT Probe Characteristics
The Spring Probe (2852) has a probe bushing with a screwdriver slot to facilitate tightening into place. A drop
of anti-seizing lubricant on the threads before installation will ease installation, and subsequent removal. When
installing Spring Probes be sure you have correctly identified the standard thermo-well. Some aircraft have fuel
primer ports with the same thread size.
Many factory-installed CHT displays utilize a single threaded or bayonet-style resistive type probe that
occupies one of the thermo-wells. This probe is not electrically compatible with the thermocouple probes
required for the Graphic Engine Monitor.
A Spark Plug Gasket Probe (2853) may be used on this cylinder for the GEM series Display, so as to allow the
factory-installed display to remain functional.
The Spark Plug Gasket Probe replaces the standard copper spark plug gasket on one spark plug in the select-
ed cylinder. The spark plug chosen should be the one that provides the best correlation with the other
temperature probes. On common downdraft-cooled engines the selected cylinder will be the upper plug. Allow
enough wire length to move the probe to the other plug if necessary.
The Spark Plug Gasket must be removed and replaced by the Gasket Probe. Annealing of the Gasket Probe is
not required or recommended, and the Gasket Probe Does Not require replacement when the spark plugs are
changed.
Alternatively, an Adapter Probe may be used instead of a Gasket Probe. An adapter probe will allow both
displays to derive their CHT readings from the same thermo-well. For this reason, use of the Adapter Probe is
recommended instead of a Gasket Probe.
If the factory-installed CHT display has a bayonet-style probe, the Insight Bayonet Adapter Probe (2855) may
be used instead of the Gasket Probe.
The Bayonet Adapter Probe replaces the original bayonet adapter. It has a screwdriver slot to facilitate
tightening in place, and placing a drop of non-seizing lubricant on the threads before installation will ease
installation and subsequent removal. Once the Bayonet Adapter Probe has been installed, the original bayonet
probe maybe locked in place with a push and a twist.
If the factory-installed CHT display has a threaded probe located in the thermo-well, the Insight Threaded
Adapter Probe (2856) may be used. The Threaded Adapter Probe is installed in the thermo-well between the
cylinder head and the original CHT probe.
Installing the Carburetor Temperature Probe
The GEM is supplementary for carburetor temperature. Install the Insight Carburetor Temperature probe
(Insight P/N 610C-021) into an existing tapped hole in the carburetor. Consult with the engine or carburetor
manufacturer to determine the probe-hole location and thread size. Ensure the probe does not interfere with any
internal carburetor components.
For G2, G3 and G4 GEMs refer to Drawing 610C-315 or G4-315 for electrical connections.
The
G1 GEM uses pin numbers "A" and "1" on the P1 Edge-Connector. In the case of upgrading from an older
GEM system to a G1 GEM check for the possibility of existing wiring to the "A" or "1" pins on the P1 connector.
Remove any existing connections to these pins and only connect the Insight Carburetor Probe. See Wiring
Diagram Drawing 1200-018 Rev. E or later.