Technical Reference Manual
Oil Pressure System- Inboard & Stern Drive
- To test the gauge, voltage from "I" to "G"
terminal must be 10-16 volts DC, with no wire
on "S" terminal. Gauge pointer should rest
below the "0 PSI" mark. Next, connect the "S"
terminal to the "G" terminal (leave "I" and "G"
terminals connected). The gauge pointer should
rest above the maximum pressure mark.
- Sender resistance can be measured to
determine the sender's correct operation.
Remove wire to gauge. Connect an ohmmeter
to terminal of sender and to engine block.
Approximate pressure sender resistance
- Zero pressure = 240 ohms
- 1/2 gauge reading = 103 ohms
- full gauge pressure = 33 ohms.
- You will get half these values on a dual
- If sender is shorted (0 ohms) gauge will read
above full gauge pressure reading.
- If sender has infinite resistance (open) gauge
will read below 0 PSI.
- If gauge reads lower than expected, was sealer
used on the sender threads? (See illustration.)
- The accuracy of the system (gauge & sender)
can be 5 PSI at 40 or 50 PSI.
- Use of pipe extenders to plumb both a sender
and pressure switch (for horn or warning light)
from one port is not recommended. Pressure
readings will be accurate, but the weight added
to the extended fitting of a vibrating engine may
cause fatigue related break age.
- Teleflex does not offer senders for metric
- Dual Station installations:
- When replacing one gauge in a two station
installation, the second gauge may need to be
replaced as well.
- Mixing two gauges from different manufacturers
to one sender may cause an error in both gauges.
- If one gauge fails the second gauge will read
much higher than expected.
- If sender fails "open", both gauges will read
below the "0" mark.
- If sender fails "short", both gauges will read
above the "full pressure" mark.
- Twin engines: it may be helpful in
troubleshooting to switch either the senders or
the gauges from engine to engine.
Oil Pressure Sender I.D. Guide
Use this chart for field identification of Teleflex
pressure senders. (ID code stamped on wrench hex
of sender. See illustration below chart.)