Pilots and owners should not perform aircraft maintenance themselves unless supervised by a licensed mechanic. Before replacing an aircraft sensor, ensure the existing one is not working due to a simple issue. To test an RPM sensor, check that it is fitted to the correct magneto vent plug and produces the appropriate RPM reading for the engine type. Inspect wire connections and boots for issues causing intermittent readings. Follow installation instructions carefully when replacing a sensor. Conduct engine tests after installation to check for ignition system malfunctions before flight.
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Installation of rpm sensor for slick magneto
1. Pilots and owners of aircraft unless licensed as airframe and powerplant mechanics
should ideally not be installing or doing maintenance work on their own unless
supervised by competent person.
Before you decide to buy a new sensor, make sure the existing one hasnt stopped
working because of some silly reason.
Start with ensuring that the Aircraft Sensor Systems is fitted to the correct vent
plug of the slick magneto. When you peep into the vent, if you see gear instead of the
rotating magnet, then the RPM sensor is fitted on the wrong vent.
If the RPM sensor produces a reading, it
should be in this range:
3600 rpm for a 4-cylinder engine
2400 rpm for a 6-cylinder engine
1800 rpm for a 8-cylinder engine and,
1600 rpm for a 9-cylinder engine.
1800rpm for a 4-cylinder dual magneto
engine and
2400 rpm for a 6-cylinder dual
magneto engine.
The red wire from the RPM sensor
should be connected to a 5-volt supply.
Check for oxidation on the male/female spade connectors between the RPM sensor
and the gauge harness. Sometimes, oxidation can result in intermittent RPM
reading.
2. Test the ignition wire boots and caps to check continuity.
If you are convinced that you do need to install a new RPM sensor for your Slick
magneto RPM Standard Sensor for vent plug for Slick magneto (JPI part # 10-
05652); start with:
1. The rotating magnet will have a vent plug remove that.
2. Make sure you have removed the plug from the correct vent by:
3. Peeping into the vent and ensuring that you are not seeing the gears. You
should only be seeing the rotating magnets.
4. Insert the speed sensor into the vent port and initially use your fingers to
tighten then tighten 1/8 turn.
5. After installation, when you fire up the aircraft engine, the RPM Gauges in the
cockpit should be in the ranges mentioned above in this article.
6. Route the wires back towards the firewall avoid attaching the wires directly
to the ignition.
7. Sufficient slack should be provided in the wire bundle to allow for engine
movement between the engine and the engine mount.
8. Connect the wires to the corresponding coloured wires in the Slimline
Instruments harness.
Once everything is installed, you need to test the engine prior to take off. Any
malfunctioning in the ignition system can be identified by observing changes in rpm
that occurs when the ignition switch is moved from both to right and then from
both to left. A small variation (decrease) in engine rpm is normal during this test.
The permissible decrease is listed in the AFM or POH.
If the aircraft engine stops running when switched to single magneto or if the rpm
drop exceeds the prescribed limits, do not fly the aircraft until the problem is
resolved.
It should also be noted that no variation in rpm is not normal and the aircraft should
not be flown.
To buy the latest RPM sensor for Slick Magneto, please visit:
https://www.jpinstruments.com/shop/rpm-sensor-for-slick-mag/
JPI Sales:
1-800-345-4574
714-557-3805
FAX: 714-557-9840
sales@jpinstruments.com