Hedge Trimmers

There are several things that can cause a non start condition. First you need to determine if it is a fuel supply, compression, or ignition problem. Just throwing parts at the problem without testing can get very expensive which why it is advisable for users to have a good 2 cycle tech to check out these engines. They will have the necessary tools and experience.

• Does it start with fuel mix added to the cylinder via the spark plug hole? Here I see that you already replaced the carburetor so this should not be the issue.

• Is the spark arrestor screen on the muffler clean?

• Also remove the muffler and check the piston, cylinder, and ring condition.
  • If the ring is struck or the piston/cylinder badly scored then the engine will not have enough compression to start.
  • These engines needs at least 100 psi to start.
  • If it is just a struck ring and the piston/cylinder are clean then it simply a matter disassembly cleaning the piston and ring, and reassembly.
  • If the piston/cylinder are badly scored then a new PNC (piston and cylinder) are needed.
  • Crankcase also may need pressure/vacuum tested as air leak can also cause a non start condition.

• Then there is ignition timing which can be off if the cast in flywheel key is sheared.
  • Can be easily checked by pulling the engine through until the piston is at the top of it stroke. When the piston is this position the magnets on the flywheel should line up with legs of the ignition coil.
  • If they don't then remove the flywheel and check it built in key. If sheared then replace the flywheel.
  • Also remember to re-torque the flywheel nut to a torque of 25–35 Nm.(18.439-25.814 ft-lbs). Under tightening will result in the key shearing and over tightening will result in flywheel damage.

• One last thing to check which is rare is the flywheel magnet strength.
  • They should have a strong pull.