series 3 missfire

well as the title says, Ive got a 24volt ex army series 3, 2.25 petrol, runs fine on tickover, and holds speed when the rev's are up fine, but accelerateing through the gears its really putt putt putt and spluttery it feels like its holding back, now if you pull the choke out slightly its not right but not so bad, any ideas what this could be

regards fenman....

poor spark

so whats the cause of a poor spark, Is it as simple as just changeing the plugs the plugs??

webbedfootfenman said:

so whats the cause of a poor spark, Is it as simple as just changeing the plugs the plugs??

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sounds more like points, dizzy cap or rotor arm. You need to start at the coil and then work your way down to the plugs.

Check the spark on the end of the king lead first. If the spark is good and strong, compare it with the spark you are getting at the end of each of the HT leads. If the spark is the same then pull the plugs and take a look. If it's weaker, pull off the dizzy cap and check for scoring on the dizzy cap contacts and the end of the rotor arm. Using a pair of insulated pliers Hold the Ht lead just above the rotor arm so it's not quite touching. If there is a spark when the engine is cranked, the rotor arm is buggered.

You can operate the points with a screw driver to see if they and the condenser are working ok. You can also check the gap is ok. On most coil engines the gap should be 0.015" . On enegine with a magneto it is usually 0.012".