What to do when a lawnmower pull cord stuck
Do not run the engine until the string is released when a lawnmower pull cord is stuck and cannot be pulled. If you must use force to loosen it, unplug the spark plug cable first so that if there is a backfire, there will be no explosion.
You should never use your hands or feet to yank on a stuck rope, as this can cause major injuries such as fingers being ripped off of your hand, which could require amputation to fix.
Run around to the opposite side of the lawnmower and locate either one or two nuts holding down a metal plate covering where the starter rope enters the engine (sometimes called flywheel cover). Unscrew both nuts by hand and lift up the plate.
Run your fingers along the starter rope inside the engine compartment to feel for the knot or jam that is keeping it from being pulled out of its spool. If you do not find anything, try slowly pulling on the starter cord again.
If you still cannot find where the string is jammed, look around for other possible areas where it could be jammed. For example, pulling on a stuck lawnmower pull cord can cause major problems with internal connections within the engine itself, which are very sensitive due to their complicated nature.
Once you have found where your string is stuck, enter into one of two categories: if your lawnmower has an electric start system, then skip this step and go directly to replacing or cutting off the old pull cord.
If your lawnmower uses a pull cord to start it, cut off the stuck string as close to the engine housing as possible without cutting into an internal line or wire. Leave enough of the cord sticking out that you can tie on a new end.
Take some masking tape and wrap it around where you just cut the rope to avoid sharp edges or points left exposed.
Tie your new starter rope onto the engine compartment metal plate with two square knots – one on each side of the plate, allowing 8-10 inches free length between knots is good. Be sure not to tie too tight around this metal plate because if you do, it could cause damage to the internal wires attached here. Likewise, if nothing happens after replacing the pull cord and you cannot get your mower to start, it could be the result of having tied the rope too tight, which caused internal damage.
If this is the case, then cut off the new starter rope that you just installed and followed these steps again but tie a single knot at one end instead of two knots on either side of the metal plate.
Once you have successfully replaced or cut off your old lawnmower pull cord and secured a brand-new starter rope to where it enters into the engine compartment, screw back down onto place loosely both nuts holding down metal flywheel cover. Carefully run your fingers underneath each nut while doing so to ensure it is securely tightened – do not tighten one nut before tightening the other, or you could tighten it down too much, which could cause damage to internal components.
Look for any areas where your starter rope is getting caught on anything. If there are no snags, then line up your lawnmower pull cord with the notch in the starting mechanism and press it into place, allowing removal slack until you hear a click. This ensures that there is nothing between your lawnmower pull cord and the starting device inside of it when this happens. Finally, plug in your spark plug cable back into its slot underneath the metal flywheel cover.
Begin pulling out the new lawnmower pull cord again by hand until you feel resistance once more. Maintain a firm grip with one hand and reach down with the other to pull the starter cord out as far as you can, which should loosen it.
Start your lawnmower by pressing down on its handlebar throttle control knob and allowing it to reach top speed before pulling on the new lawnmower pull cord. This prevents damage from being done from a lawnmower running at high speeds that are being pulled by an already-tight rope.
Keep a firm grasp on the starter cord for between 30 seconds to a minute so that it doesn’t spring back into place too quickly if the engine kicks off too early before it has warmed up, which would result in difficulty starting later on as you see fit press down further onto engine handlebar throttle control for between 10 more seconds to another minute.
This method should provide enough time for your engine to pick up, but do not allow it to run at its highest throttle setting more than 4-5 seconds, or you risk breaking the lawnmower pull cord again. Once you have allowed your mower to warm up, press down on the handlebar throttle control one last time and then release the starter cord from hand grip. Allow new lawnmower pull cord spring back into place by itself once mower is already running until it clicks into position inside of starting device, which indicates that you can now safely move about freely while using a lawnmower with a newly installed starter rope.
If you can still get your lawnmower to start by pulling the starter cord out yourself, there is likely an issue with its starting device and not with your new replacement lawn mower pull cord itself. Therefore, you will need to bring it in for professional servicing or contact local technicians who specialize in small engine repair so they can diagnose potential issues on their own.