Operating Guide Engine Operating Guide
Follow these instructions and it should provide you with many years of flying enjoyment.
Always use a premium gas and 2 cycle oil mix of no less than 40:1 and no more than 32:1. Any more oil than this and you risk fouling the sparkplug and excessive smoke. Any less than 40:1 and you risk over heating, galling or etching of the piston and cylinder wall and seizure.
It is recommended that you use a kill switch and connect it's wire to the coil so that you may put a switch between this wire and a wire that is grounded to someplace on the engine or motor mount. For safety purposes, this will allow you to stop the engine manually by killing the ignition at any time you wish without relying on your radio control. It is also possible to set the carburetor so that you can kill the engine merely by moving the throttle control to the extreme low end. Some modeling events require the ability to positively stop the engine either manually or by remote control or both.
If you elect to connect the electrical “kill” switch to a remote control channel, be sure to keep at least 4 inches of insulation between any metal connections to the engine and any radio system components. That means do not use solid wire throttle or kill switch pushrods. Always use a section of plastic between the carburetor or kill switch connection and the servo connection. I always try to get 4” of plastic “Nyrod” in there somewhere. Remember high tension ignition noise can transmit through anything that is metal. The use of resistor spark plugs significantly reduces the strength of this noise. The front-mounted magneto does a very good job of isolating this noise. However, good practices in installation with any spark ignition engine can go a long way if other radio problems appear.
NOTE: KEEP ALL WIRES ON ENGINE AS FAR AWAY AS IS POSSIBLE FROM BATTERIES, SERVOS, ANTENNA AND RECEIVER FOR BEST INTERFERENCE FREE OPERATION. DO NOT USE METAL PUSH RODS FOR CARB ACTUATION. USE PLASTIC NYRODS. We have had excellent results with all type of R/C radios when these instructions are followed.
Installation and starting Instructions
Use 4 ounces of good two-cycle oil with one gallon of gas. This gives a 32:1 ratio which is a good conservative mixture.
Hook the gas tank feed line to the 90-degree gas intake tube on the carburetor.
Make certain that the straight tube (if equipped) next to the needle valves is closed off with fuel line and a plug in the end of the fuel line if you will not be using an inline primer bulb.
The Walbro carb (if equipped) sometimes does not have a integrated choke so you will need to have a helper place thier finger over the choke venturi then prime the engine by flipping the prop about 4 to 6 revolutions. Be sure that the airplane is sufficiently restrained during the choking operation because the engine could start. If the engine fires even once in this condition, stop flipping and have your helper move thier finger to "half choke". However, some engines come with a carb with a choke in which case you of course do not need to use you finger for this function.
Start your engine with a standard 12 volt starter. Open the choke all the way after the engine has run for a few seconds.
Tips on Do's and Don'ts
Stop the engine by shorting the kill switch or closing the throttle all the way. NEVER throw anything into the propeller to stop the engine
I found that using a velocity stack on the carburetor improved the performance a lot. The prop blast of air going past the flat side of the carburetor will suck the fuel air mixture out of the carburetor, causing the engine to run lean. Using a velocity stack will cure that problem. (Included on some engines)
To adjust the ignition coil gap, a business card can be used to set the gap between the magnets and the coil.
Remove spring and throttle idle stop screw from carburetor throttle so your servo will not be working to overcome the spring.
Use 87 to 93 automotive gas. DO NOT USE NITRO, the carb is not designed for nor will it handle nitro fuels.
Be sure to use fuel tanks and fuel tubing that is made for gasoline.
Using a resistor spark plug will help stop radio interference.
Don't use metal push rods to your engine from the throttle servo.
Wrapping aluminum foil around spark plug wire and spark plug will reduce interference.
Keep radio, servos, battery and switch as far away from engine as possible to help eliminate inerference. Also, it is a good way to move the aircraft c/g rearward.
With your engine running, range check your radio at a minimum of 150 ft.
You should have rock solid control surfaces, no glitching, or following the RPM of the engine.
Be sure to check the motor mount bolts after running engine to insure they are remaining tight.
As is, the engine will operate fine but if you want better performance then you should consider the following recommended upgrades:
1. A larger carb. Upgrade to a 16mm carb with a 11 to 13mm choke. This is a very popular Walbro size for chain saws and the like. Suitable carbs with the 16 &13 mm combination include Walbro WT 644, 603 & 257. Any other Walbro "big bore" carb of the same specs will work as well. Keep in mind if you install a carb with a exit larger than the intake, it will need to be drilled out to the same size or larger for the carb to be fully effective.
2. Install a Pitts style muffler if not included. The stock muffler, like the carb, is restrictive and by using a Pitts type muffler you not only allow the exhaust gases to exit the engine faster, you also shave off over half the weight of the factory steel muffler. The only drawback is the same with this type of modification to any gas engine and that is sound level will increase.
3. Although any sparkplug brand that will fit will of course work, I recommend for best performance that you use a high-end resistor plug like an E3 16 made by E3. In my opinion the best plug available for this engine.
4. For the ultimate in power and performance try using an electronic ignition system. Not only does it allow you to adjust the timing for maximum power, it also lets you do away with the heavy flywheel and coil as well as letting you run the engine in either direction!
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