Read on to get more troubleshooting, but try all the earlier simple things before moving on.
Cleaning points on an old engine
Most modern engines have an electronic ignition system. According to Briggs and Stratton, this usually applies to engines manufactured after 1983. The engine below is probably about 40 years old and the points need to be cleaned.
- Dirty contact points can prevent a spark from occurring in the plug. The points on a motor are basically a switch that opens when the current through the coil of the spark generator device (ignition coil or magneto) is at its maximum point. This creates a voltage spike in the spark plug. These points can be stained or corroded and bored over time and should be cleaned. A rubber oil seal is installed at the crankshaft exit point from the sump and top of the engine block. If the engine tends to fail (no sparks occur in a cycle), it may be due to the oil getting out of this seal and splashing over the dots. A puddle of oil in the point compartment is evidence of this. It's kind of like a test to get to the points that are usually under the steering wheel of the engine.
- This mower has been stored in a leaking shed and rusted up for over 20 years without being started. I'm going to check out the points and carburetor to see if it's ok. This machine has a pump-and-weir type carburetor.
- This mower has been stored in a leaky shed and has rusted for more than 20 years without being torn off. I'm going to check the points and the carburetor to see if they're okay. This machine has a pump-type carburetor and weir.
- First, remove the mesh on the flywheel.
- First, remove the mesh on the steering wheel.
- Prise off the plate covering the ratchet mechanism.
- Award plate covering the ratchet mechanism.
- Remove the steel balls which form part of the ratchet mechanism. If they are rusted, clean them with fine wire wool and add a little light machine oil when replacing.
- Remove the steel balls that are part of the ratchet mechanism. If rusty, clean with fine wire wool and add some light oil to the machine when replacing.