Small Engines (Lawn Mowers, etc.): Toro Push Mower Pull Cord Wont Pull, briggs stratton, proper tension

Question
The pull cord can only travel a few inches. I removed the metal cover and the cord pulls freely, but when reattached to mower body there are 2 silver arms which come out when pulled and are catching something and locking up. Can only get cord to pull a few inches. Any idea how to address?
Toro, Model 20511, 21" Rear Bagger

Answer
Mike

Broken starter ropes or failure to retract are both repairs that are fairly easy. However, the spring can be nasty as it is under tension (or should be when reassembled). This can be risky if you are not familiar with the internal construction as you disassemble the unit.
The cause of a broken cord is obvious. The cause for a failure to retract could be a broken spring, tangled or frayed rope, or some other mechanical failure. A broken spring will require total disassembly of the starter mechanism - fortunately there really isn't that much involved.

With some designs, it is possible to replace the cord without fully disassembling the starter mechanism - by threading the cord in and tying a not in the end - but after rotating it several turns to put the proper tension on the spring. This is relatively safe but may be frustrating as 3 hands are sometimes needed.

Where safe disassembly is not obvious, I would recommend that you refer to a book on lawn mower or small engine repair from the library or the service manual for the mower, if possible. You may be able to find specific step-by-step instructions which will minimize your risk of injury from an encounter with an uncontrolled spring.


When the rope pulls out and retracts normally - but doesn't do anything else - the most likely cause is a problem with the one-way clutch. This may be part of the spring-rope assembly - usually removable as a unit - or attached to the flywheel. The most common problems are gummed up lubrication or a broken spring or other damaged or worn parts. For common engines:

On Briggs & Stratton starters, the clutch is often part of the flywheel nut assembly. The entire unit can be easily removed and replaced if it fails to engage reliably.

On Tecumseh starters, pawls in the starter assembly engage a serrated cup held in place by the flywheel nut. Check for damaged parts or gummed up lubrication.
WARNING: Take extreme care should you need to disassemble the portion of the starter that includes the mainspring - that can be nasty.