Thanks NormK for the advise. I did buy a new plug but to my disappointment, it still won't start. I tried testing the plug out of the motor whilst connected to the plug wire and i can't seem to see any spark. So it could be something else on the electrical circuit. Next thing i'll be checking is if all the wirings are still connected. How do you know if the plug wire are still good ? Any other components that i should check ?

In the past, if i couldn't get it to start, i removed the spark plug and put in a few drops of petrol and re install the spark plug. it has worked for me on several occassion..