0331635 JOHNSON SCREW, Spark lever stop

Maintenance of the spark plugs is required in order to achieve the following benefits:
Normal fuel consumption
Normal level of emissions
Maximum service life of the spark plugs
Stable operationThe service life of the spark plugs is affected by fouling due to deposits from the oil and by peak voltage. Maintenance of the ignition system is also affected by voltage. Higher voltage is required by higher inlet manifold air pressure, a higher compression ratio, and a leaner air/fuel ratio. Higher voltage reduces the service life of components such as spark plugs, wires, and transformers.Removing the Spark Plug
Standard Ignition System
Turn the ignition switch to the "OFF" position to ground the magneto and discharge any capacitors that may be charged.
Illustration 1 g02657458
(1) Seal
(2) Wire
(3) Transformer assembly
(4) Spark plug
(5) Boot
Pulling on the wiring harness may break the wires. Do not pull on the wiring harness.
Disconnect the wire from the transformer. The wire may break if you pull on the wire.
Remove the boot and remove the extension.
Pressurized air can cause personal injury. When pressurized air is used for cleaning, wear a protective face shield, protective clothing, and protective shoes.
Ensure that the area around the spark plug is clean and free of dirt and debris. Thoroughly remove any debris. Use compressed air. The maximum air pressure for cleaning purposes must be below 207 kPa (30 psi). The spark plug can also be cleaned with a nonmetallic brush.
Use a spark plug socket with an extension in order to remove spark plug.
The use of a thread tap will remove metal unnecessarily. This will also reduce the heat transfer for the spark plug. This can result in a reduction of the spark plug service life and a reduction of the detonation margin.
If the spark plug resists removal by hand, apply penetrating oil to the threads. Use the wrench and apply steady pressure to the spark plug until the spark plug is loose.If it is difficult to remove the spark plug by hand, clean the internal threads with the 154-9521 Spark Plug Seat Cleaner. This tool scrapes debris from the seat and from the threads in the spark plug adapter. Be sure to remove any debris from the cylinder.CSA Ignition System
Note: The CSA ignition system is equipped with an integral transformer. The transformer screws onto the spark plug. The transformer and the spark plug are removed separately. The transformer and the spark plug are installed separately. Do not overtighten the transformers.
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CSA Ignition System
(6) Wiring harness
(7) Boot
(8) Transformer
(9) Copper washer
(10) Spark plug
(11) Spark plug gasket
Turn the ignition switch to the OFF position.
Disconnect the wiring harness.
Remove the boot.
Remove the transformer.
Ensure that the area around the spark plug is clean. Ensure that the area around the spark plug is free from dirt and debris. Remove spark plug and remove gasket from the cylinder head. Remove the gasket and remove copper washer . Discard the gasket and discard the copper washer. Inspecting the Spark Plug
Illustration 3 g02657482
(12) Terminal post
(13) Insulator
(14) Shell
(15) Gasket
(16) Electrodes Inspect the spark plug closely for damage. The condition of the spark plug can indicate the operating condition of the engine.The terminal post must not move. If the terminal post can be moved by hand, discard the spark plug. Inspect the insulator for cracks. If a crack is found, discard the spark plug.Faint marks may extend from shell onto the insulator. The marks may be a result of a corona that forms at the top of the shell. The conductor will develop a corona when a very high voltage potential ionizes the air. The corona is a normal condition and is not an indication of leakage between the shell and the insulator.Inspect the shell for damage. Cracks can be caused by overtightening the spark plug. Overtightening can also loosen the shell. Discard any spark plug that has a shell that is cracked or loose.Inspect the electrodes for excessive wear. Flat surfaces with sharp edges provide the best conditions for creating a spark. Cat spark plugs have precious metal tips on the ends of the electrodes and the ground strap. This material will gradually erode. Use extreme care when you set the electrode gap. Maintain even spacing and proper alignment between the two precious metal surfaces. Replace the spark plug if the precious metal is worn off.A light brown deposit or a beige deposit is produced by normal operation. White deposits or gray deposits may be caused by the following substances:
Excessive oil
Use of the wrong oil
A substance that is introduced through the fuel system or the air systemA spark plug can operate despite a buildup of ash. However, a buildup of ash can cover the electrode gap causing a misfire. Large deposits may retain heat which can cause premature fuel ignition and lead to uncontrollable detonation.A standard ohmmeter (9 V) can be used for measuring the resistance of the spark plug. The ohmmeter can be used only for spark plugs with wire-wound resistors. It is not possible to use a standard ohmmeter (9 V) for measuring the resistance of other types of spark plugs. Measure the resistance between terminal post and electrode. Discard any spark plug with a wire-wound resistor if the resistance is outside the range of 1000 to 1500 ohms.Cleaning the Spark Plug
Thoroughly clean the spark plug. Do not use a metallic wire brush. Glass beads are the preferred method for cleaning.Follow these guidelines for the use of glass beads:
Always use clean glass beads.
Use care in order to clean only the electrode and the insulator near the electrode.
Do not use glass beads on the outside of the shell or on the upper part of the insulator.Installing the Spark Plug