Powerplant; Engine Cowls; Engine Removal & Installation - WACO YMF F5 Series Maintenance Manual

SECTION 7
7.1

ENGINE COWLS

Proper maintenance is an essential requirement to get proper service and long life from the NACA cowl.
At each engine check the felt pads should be carefully examined and kept in good condition to make sure
there is no metal to metal contact between the cowl and the engine. We use deicer boot adhesive
cement to make the felt pads adhere in their proper location, and if these come loose from time to time,
they should be replaced with new pads.
The cowl should be kept snug with attachment fittings uniformly adjusted so as to distribute the load over
the various fittings, rather than having one tight and carrying the entire load. It is well to remember that
the engine expands when hot and it is better to be a little on the loose side than to have them too tight.
The cowl should not vibrate in flight and if it is observed to start vibrating or shaking, steps should be
taken to correct the condition causing this problem. Sometimes it will be found in a rough propeller or
engine rather than in the actual cowl mountings.
7.2 ENGINE REMOVAL & INSTALLATION
The procedure for removing the engine is the same for both the R-755B2 and the R-755A2
engine. All hardware, controls, hoses, fuel and oil systems are identical in both cases. The
procedure is as follows:
(a) Remove cowl
Disconnect engine controls – throttle, mixture and carb heat
(b)
(c) Disconnect fuel and oil lines
(d) Remove exhaust system
Disconnect electrical connections – mag P leads, battery ignition lead, alternator
(e)
(f) Attach hoist using Jacobs engine sling (see Illustration No. 4, page 25)
(g) Lift the engine slightly, remove engine bolts and swing engine free of engine mount
Installation procedure is the same for both the A2 and B2 engine models with the exception of
the mounting bolt length as follows:
(a) Lift the new engine into position using the Jacobs engine sling
(b) Install new mount rubber cones SA22387 (16)
(c) 1. For the R-755A2, Install new AN6-45 mount bolts (8) and AN310-6 Nuts (8) and cotter
pins. Tighten the AN310 nuts until there is approximately 1/8 in between the large
washer under the head of the bolt and the edge of the mount rubber cup (see Fig. 7.2)
and the cotter pin hole in the bolt aligns with a castellation in the nut. Install the cotter
pin.
2. For the R-755B2, Install new An6-35 mount bolts (8) and AN310-6 Nuts (8) and cotter
pins. Tighten the AN310 nuts until there is approximately 1/8 in between the large
washer under the head of the bolt and the edge of the mount rubber cup (see Fig. 7.2)
and the cotter pin hole in the bolt aligns with a castellation in the nut. Install the cotter
pin.
REVISION: H
RELEASED: 07/21/2017
WACO Classic Aircraft Corporation
YMF WACO F5 SERIES MAINTENANCE MANUAL

POWERPLANT

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PART NO. YMFAMM-1