I own a Jonn Deere lawn mower, type F510. Product info: MOF 510A150332, engine Kawasaki PA 420A-BS02, eng. nr. PA420A009649.
Problem: the engine starts very difficult and when running will not accelerate at all and backfires continiously with blue flames in the carburettor. The coil and the ignitor were already replaced without any result.
The carburettor is spic and span and there is no water in the fuel.
Compression is o.k, +/- 7 bar.
When the motor is running, manual activation of the choke and throttle valve have no influence on the engines behaviour.
The spark is provided by the coil only, because the moment the ignitor is connected the engines dies.
Regards/ J. Smit