Lately my 1996 JD425 AWS engine started misfiring under load. A year ago I totally rebuilt the Kawasaki FD620D-AS02 engine with oversize pistons and rings, new intake and exhaust valves and springs. I only use 91 non-oxy gasoline and tried changing the spark plugs from NGK BM6A to NGK BM4RA as recommended by Kawasaki. So I now wonder is there something that changed in the timing!! Is it possible to adjust the engine timing without adjusting the timing gear? Any suggestions appreciated. Thank you.
You get a small amount of timing variations with the coils.
The smaller the gap the further advanced the spark will be and visa versa.
What does give you grief is the diode between the coils on twin cylinder engines.
The test is to pull the kill wires from the coils and do a test mow.
Problem goes away then it is a wiring problem.
