Rotax 912 ULS 3 - Inspection for Correct Priming of Hydraulic Valve Tappets

Effectivity: 912 Series
Edition 1 / Rev. 0
d04055
page 79
May 01/2007
BRP-Rotax
INSTALLATION MANUAL
- Release the pressure from the oil tank.
- Un-block the oil return port on (5) the oil tank and reconnect the engine return
oil line (2) to the oil return port on the oil tank.
■ CAUTION: Ensure that the oil suction line (1) and engine oil return lines (2)
are connected to the proper fittings on the oil tank. If the oil lines
from the engine to the oil tank are incorrectly connected at the
oil tank, severe engine damage may result.
- Replace spark plugs and restore aircraft to original operation condition.
- Residual oil will have accumulated in the crankcase, return it to the oil tank
by following the oil check procedures in Operators Manual (or SI-27-1997 Oil
level check for ROTAX engine type 912 and 914 (Series), current issue).
- Add oil to engine oil tank to bring the oil level up to the full mark on the dipstick.
▲ WARNING: Carefully check all lubrication system connections, lines and
clamps for leaks and security.
13.11)Inspection for correct priming of hydraulic valve tappets
See Fig. 52.
The subsequent check procedure describes the correct method to verify
adequate priming of hydraulic valve tappets.
■ CAUTION: Engine has reached operating temperatures here. Use appro-
priate safety equipment and clothing.
- Remove valve cover on cylinder 1.
- Turn crankshaft in direction of normal rotation so that the piston on cylinder
1 is on ignition top dead center (both valves are closed).
- Press on push rod side of rocker arm with a force (F) of about 70 N (15.0 lbf.)
for about 3 sec. Approximate force can be verified with a fan belt tester.
Repeat on other rocker arms.
- Check distance between rocker arm and valve contact surface. Max.
allowable distance 0,5 mm (0.02 in.).
- Repeat on all other cylinders.
■ CAUTION: If it is possible to push the valve tappets further than this limit,
an additional engine run for about 5 min. at 3500 rpm after
refitting the valve covers. To get the hydraulic valve tappets
primed, this process can be repeated another 2 times.