User Manual

PAGE 8 OF 22
The average mixture settings are 1&1/2 turns out for the low speed circuit (See No. 4), and 1&3/4 turns out for the
high speed circuit (See No. 5). Carburetor mixture adjustment starts with the low speed circuit. The low speed
should be set such that the transition from idle to full throttle is smooth, even if the throttle is snapped to full. This
will likely result in a slightly rich idle mixture but you're better off with that than a rough transition. If the engine dies
when the throttle is advanced, the mixture is likely too lean. If the engine stumbles when the throttle is advanced,
the mixture is likely too rich. Since the low speed mixture has some effect on high speed mixture, always adjust the
high speed after adjusting the low.
The high speed circuit is properly adjusted when the engine can reach maximum rpm while in the air, which is
usually slightly richer than when it is on the ground. A general rule of thumb is to richen from the maximum on the
ground rpm by about 200rpm. If ever the engine slows or dies while at full throttle, the high speed mixture is likely
too lean and you should adjust it as soon as possible or damage can result.
NOTE: Be careful not to run the mixture screws in too far as damage to the screw and / or carburetor body may
result. Also, don't be tempted to run an overly rich mixture. Gas engine lubrication comes from the oil concentration
in the gas, not from a rich fuel / air mixture. If you want more lubrication, you can vary the oil mix ratio. A too rich
mixture will only result in poor engine performance and a fouled plug and combustion chamber.
STARTING THE ENGINE
COLD Step 1: Close the choke, advance the throttle to very slightly above the idle position, turn on the ignition and
briskly flip the prop through compression until the engine fires and then dies. If the gas line is dry, this may take 20
or more flips.
Step 2: Open the choke and briskly flip the prop through compression. The engine should start in just a few flips. If
it acts like it wants to start but doesn't, you may need to advance the throttle slightly.
WARM Open the choke, advance the throttle to very slightly above the idle position, turn on the ignition and briskly
flip the prop through compression. The engine should start in just a few flips. If it acts like it wants to start but
doesn't, you may need to advance the throttle slightly.
NOTE: It is possible to flood the engine by over choking. In this case, the spark plug must be removed and dried of
excess fuel. Make sure to have the ignition off when removing the spark plug.
ENGINE MAINTENANCE
Fuel tubing throughout the fuel system should be changed periodically and should never allow any air to enter the
system. If your gas line starts to get hard, soft or changes color, there's a good chance it needs to be replaced.
Keep in mind that the tubing inside your tank deteriorates more quickly than anywhere else in the system.
The exterior of the engine should be kept clean and inspected regularly. Tucked away inside the cowl, it would be
easy to miss loose nuts and bolts without frequent inspections. Dirt inside the cowl area can easily find its way into
the carburetor. It should be kept clean and free of dirt build up.
The carburetor fuel screen should be cleaned periodically also. Carefully remove the pump cover (inlet side of the
carburetor), gasket and pump membrane. The screen will be visible and can be cleaned after careful removal. If
ever the carburetor seems to need frequent mixture adjustment or acts like it's starving for fuel, a dirty screen is a
likely candidate for a cause. The carburetor should be inspected, cleaned or reconditioned with every flying season
or after being stored for a long period of time.
The spark plug should be inspected, cleaned and gapped periodically and replaced if it is fouled or worn. A new
plug with every new season is a worthwhile maintenance step.
ASSISTANCE
Additional information and the latest version of this manual are available at TATES PERFORMANCE HOBBIES
and answers to specific questions can be obtained by email at
[e-mail] or by phone at 03 522 4201.
#4 - Running the Engine on a Test Stand
The engine mounts supplied with the DL engines are designed to be used on an airframe intended for use with a
50cc/100cc gas engine. Running your engine on a test stand may very well cause them to fail. A typical test stand
does not allow the vibration energy produced by the engine to dissipate as it would if mounted in an airframe. As a
result, this energy causes undue stress to be exerted on the mounts and they will likely fail if run long enough.
When properly used, the engine mounts will provide trouble free operation. Our own experience has one set of
original mounts still performing flawlessly after over 176hrs of vigorous use.
Improper use of the engine or its parts may result in injury and property damage. Please read and follow all items
presented in the operating instructions. This is important for your safety as well as your enjoyment of the engine.