Push lawn mower crank cord won't pull?

Question

Mower worked fine during last use. Now, when I pull the crank cord, the cord will not budge. There is not any obstruction in the blade area. Curiously, if you remove the sparkplug, the crank cord pulls freely as it should. Putting teh sparkplug back in causes the crank cord to freeze. What does this mean and how do I fix it?

Answer 1

Sounds like your valves are frozen shut. An internal combustion engine is like an air pump. When it's running, it sucks air in through the intake manifold and the piston pumps it out through the exhaust. If the valves aren't opening, the air in the cylinder can't escape. This would prevent the motor from turning with just the little bit of torque provided by the pull cord. When you take out the spark plug, air is allowed in and out of the cylinder, allowing the engine to turn freely.

Answer 2

check the flywheel brake cable,it's your "dead man " switch you have to hold it while you mow.or the motor stops,see if the cable has broken or slipped.........tom

Answer 3

Take off the cover  then pull the rope, you can then rule out if it's an engine problem. You will more than likely find the problem to be in the pull start mech. or the safety brake cable or safety brake mech.

Answer 4

It means there is too  much compression. Remove the cylinder head and scrape the carbon buildup off using a plastic (not metal) scraper. Also clean off the top of the piston and valves. Use a new head gasket when you put it back together and torque the head bolts according to the manual.

If you don't have a manual or a torque wrench, take it to a shop and get it done right.

Answer 5

This has happened to me before as well. For my mower, there was a problem at the point where the crank cord reaches the lever you have to pull down to start it. A tiny pin was out of place on the left side of the lever, which caused the mower to not know if the lever was pulled down or not and thus, as a safety feature, allowed the crank cord to not budge. But naturally, if the sparkplug is not in tact, then there is no need for that safety measure because the sparkplug is the safety measure of all safety measures, nothing works without it. So in conclusion, check all aspects of the mechanism that starts the mower, especially the lever