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We obtained this Quadra Q42 with a 8-Ball model (designed by Dave Reid of Phelps, NY). As received the engine did not run. Not what we expected, but a fact. Close inspection of the fuel tank showed that the fuel lines were not correct. Connecting the carb up to the correct tank line (instead of one of the two vents) still did not fix the problem. The electric starter was used, but no fuel was going into the carb.
The carb was dismantled and cleaned up. Fuel residue had clogged the jets, needle seats, the screen and the pump/valve assembly. The carb was cleaned in the ultrasonic cleaner and diaphrams replaced with new ones.
The fuel dilevery problem was now fixed, but the engine still didn't even backfire!
The plug was checked for spark by rubber banding the plug to the side of the engine case. Again, the starter was used to rotate the engine. No spark.
Spare points and condenser were ordered and installed. Still no spark!
Now what?!
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A volt ohm meter was used to verify the continuity of the wiring.
The high voltage coil should measure about 7 ohms between the black lead (normally connected to one of the magneto coil mounting screws) and the center conductor of the high tension wire. The original one that came with the engine measured "OL" meaning an open circuit.
Oh well, $43.00 later with a cleaned carb, new diaphram, new points and a new high voltage coil. The engine runs perfectly.
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The ohm meter can be used to verify the points and condenser as well. With the meter connected one lead to the engine frame and the other connected to the wire lug on the high voltage coil, the resistance should vary between a dead short (points closed) and "OL" (open circuit - infinite resistance) when the engine is slowly rotated. |
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Here is the engine installed in the 8-Ball airframe. The red and black wires are used for the safety shutoff switches (one external the other controlled via the transmitter.) One lead goes to the engine case, the other to the wire lug on the high voltage coil. Shorting these two wires together shuts the inition off and the motor stops. The two shutoff switches are wired in parallel. |
Last updated: 1/2/04
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