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Valach VM 120 B2-4T Instructions
5
Mounting the intake RAM tube
The loosely supplied intake RAM tube , has to be mounted to the engine in any
case! Without it, the engine runs too lean, even with wider opened jet needles!
The carburetor screws have the right length to attach the intake RAM tube. Without
the intake tube, the screws are too long and the carburetor sits to loose on the engine.
Mounting the prop shaft
The prop shaft is supplied loose with the engine, because of ease of transport. The prop
shaft has to be screwed into the hub with a medium strength threat locking adhesive
(Loctite 642). At first screw all 6 prop screws fully into the hub. Then screw both prop
nuts onto the shaft and lock them against each other. Apply the threat locking on
the threat of the prop hub, screw it in the hub and tighten it with the help of the two
nuts. It is sufficient to hold the hub with a strong hand while tighten the prop shaft.
Installation
Mount the engine with M6 screws with matching length directly onto the firewall.
Do not use the engine if any of the four screws is not in place. Check regularly, if all
screws are securely tightened. We recommend the use of lock washers DIN 127 or a
threadlocking with a medium strength (Loctite 642).
To move the engine forward if necessary, stand off`s are supplied with the engine.
Do not use longer standoffs, they are torsionally not stiff enough and cause a lot of
vibration in many circumstances. If necessary built an engine dome.
Do not use rubber shocks! They are not needed with this engine and you save a lot of
trouble with unsuitable rubber motor mounts. Mounted rigid, the VM 120 B2-4T runs
much smoother than any two-stroke engine.
Fuel tank
The fuel consumption of the VM 120 B2-4T is very low, compared to two-stroke engines.
A 500 ml fuel tank is enough for 15 minutes of flying. We recommend the use of a felt
clunk filter! Secure the Tygon
®
F4040 fuel tubing on the connections with 0.5 - 1 mm
copper wire – wind it two times around the tubing and twist it a few times.
The ignition
Mount the ignition Hall sensor with two M3 screws on the crankcase so that the sensor
reaches over the prop hub. Secure the screws with low strength threadlocking adhesive.
Connect the ignition with a battery with a voltage range from 4.8 V to max. 9 V and a
minimum capacity of 1500 mAh. The best choice are two LiPo cells (2s, 7.4 V).
In any
case, and this is important, just use a switch and no voltage controller!
Never switch the ignition on or connect the battery, when any of the spark plug
caps is not connected with the spark plug!
