Common Problems for 2 and 4 Cylinder Engines 

TOPICS:
1. Engine will not start
2. Pullcord does not pull
3. Machine is not cutting the grass
4. Pullcord pulls very easily
5. Pullcord jerks

Engine will not start: Check the oil, check the air filter, and check the gas level first. Does your machine have a primer button? If so, did you push it 3 to 5 times? Does your machine have a choke lever? Did you put it in the choke position? Is your spark plug very dirty? If you must replace it, do not use the plug that says "lawnmower" on it. There are numerous plugs for numerous engines. MAKE SURE YOU GET THE RIGHT ONE. The wrong plug can ruin your piston! If the machine doesn't start after 7 to 10 tries, chances are great that it needs further attention from a technician. Get it into a shop.

Pullcord does not want to pull - engine acts "frozen": Check your blades. Is something wrapped around the blade(s) causing binding? Your cylinder, carburetor, and muffler may be full of oil. Did you overfill your unit with oil? (Tilting your engine in the wrong direction could be the culprit, see the Service Tips page.) If your oil level is very low, chances are that somehow the machine got tilted and the oil has filled the cylinder and other places it does not belong. SAFETY NOTE: Make sure you disconnect the spark plug before you touch the blade(s). If, after checking the unit over as described above, you still can not pull the cord, you may want to have your machine checked by a technician.

Machine is not cutting the grass: Check your blades. They may be dull or worn out. Sometimes we find them on upside down. Remember, the cutting edge, the side on which you can see the "bevel", should be facing the deck. Another reason the machine may not be cutting the grass is that the RPM is not set properly. This involves a governor adjustment that should be made by a certified technician only. Incorrect governor adjustments could cause exterme engine damage that can not be repaired cost effectively.

Pullcord pulls very easily with no resistance felt: Low compression is usually the cause of this symptom. Low compression can be caused by a number of things (which are not quick fixes) such as a blown head gasket or a valve not seating and requires technical service. NOTE: Some engines are designed with "easy start", a system that allows the rope to be pulled easily. If your machine is labelled "easy start" but wont start, take it to the shop.

Pullcord jerks back in your hand when pulled, simulating the feeling of your shoulder getting ripped out of it's socket. This is a classic symptom of a sheared flywheel key. First question we would ask you is, "What did you hit?" If you don't remember hitting anything, check your blade to see if there is a noticeable nick in it. Sometimes just leveling a big ant mound with your lawnmower will cause the flywheel key to shear. When the blade is stopped (even for a tenth of a second) but the flywheel continues to turn, the key will shear. It is designed that way so that your engine does not suffer any damage. A sheared flywheel key many times affects the timing of the machine. You can pull and pull and pull on the rope but never get it started.