Electric Tachometer Installation; Tach Indicator Removal And Installation; Emi Filter Removal And Installation; Magnetic Pickup Removal And Installation - Piper PA-44-180 SEMINOLE Maintenance Manual

ELECTRIC TACHOMETER INSTALLATION (PA-44-180T). (Refer to Figure 77-2.)
The tachometer on the 44-180T is an electrical instrument which utilizes an EMI filter, and magnetic pickups
on the engines. On top of each engine is a pickup mounted to a bracket. The pickup is positioned so that it
senses the passing of the ring gear teeth. The pulse is then read by the indicator. The electrical schematic can be
found in Chapter 91.
REMOVAL AND INSTALLATION OF TACH INDICATOR.
The tachometer is located on the pilot's side of the instrument panel and is back mounted to the panel.
1. Disconnect the harness from the back of the instrument.
2. With the instrument supported, remove the four retaining screws, and withdraw the unit from the airplane.
3. The unit can be reinstalled in the reverse order.
REMOVAL AND INSTALLATION OF EMI FILTER. (Refer to Figure 77-2.)
1. Under the panel mounted to the panel support, remove the electrical connections making note of their
installed positions, and remove the two screws securing the filter.
2. Install the wires where previously noted and reinstall filter.
REMOVAL AND INSTALLATION OF MAGNETIC PICKUP. (Refer to Figure 77-2.)
1. Remove the top cowl of the desired engine.
2. Remove the screws and clamps attaching the pickup to the bracket.
3. The unit can now be removed by cutting the tie wrap and disconnecting the butt splices.
4. For installation, proceed as follows:
A. The clearance between the teeth of the ring gear and pickup should be .015 ± .005 inch with the
crankshaft pushed aft. Using a feeler gauge align the mounting clamps and pickup to give the proper
gap, and install the mounting screws.
B. Rotate propeller, making sure the crankshaft is pushed aft and insure the proper clearance is
maintained.
WHEN REMOVING A PROPELLER, FIRST REMOVE THE PICKUP TO
PREVENT DAMAGE TO THE UNIT.
PIPER AIRCRAFT
PA - 4 4 - 1 8 0 / 1 8 0 T
AIRPLANE MAINTENANCE MANUAL
— CAUTION —
3H8
7 7 - 1 3 - 0 3
Page 77-06
Revised: May 15, 1989