874257 Volvo.Penta Indicator

Ignition systems can cause electrical shocks. Avoid contacting ignition system components and wiring.Do not attempt to remove the valve covers when the engine is operating.
Removing the Spark Plug
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(1) Harness connector
(2) Bolt
(3) Transformer
(4) O-ring seal
(5) Extension
(6) Spark plug
Ensure that the mode control switch is in the "STOP" or "OFF/RESET" position.
Pulling on the wiring harness may break the wires. Do not pull on the wiring harness.
Remove the lockwire. Disconnect harness connector (1). Use pliers to turn the connector counterclockwise.
Remove bolts (2).
Remove transformer (3). Inspect O-ring seal (4). If the O-ring seal is worn or damaged, discard the O-ring seal and use a new O-ring seal for assembly.
Remove extension (5).
Pressurized air can cause personal injury. When pressurized air is used for cleaning, wear a protective face shield, protective clothing, and protective shoes.
Debris may have collected near the spark plug. Thoroughly remove any debris. Use compressed air. The maximum air pressure for cleaning purposes must be below 207 kPa (30 psi). Ensure that the area around the spark plug is clean and free of dirt and debris.
Use a 4C-4601 Spark Plug Socket and an extension to loosen spark plug (6). After the spark plug has been loosened, remove the spark plug by hand to detect problems with the threads. After the spark plug has been removed, discard the used gasket.
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 the spark plug cannot be removed by hand, clean the threads with 9U-7511 Spark Plug Seat Cleaner. This tool scrapes debris from the seat and from the threads.Inspecting the Spark Plug
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(1) Terminal post
(2) Insulator
(3) Shell
(4) Gasket
(5) ElectrodeInspect the spark plug closely for damage. The condition of the spark plug can indicate the operating condition of the engine.Terminal post (1) must not move. If the terminal post can be moved by hand, discard the spark plug.Inspect insulator (2) for cracks. If a crack is found, discard the spark plug.Faint marks may extend from shell (3) onto the insulator. The marks may be a result of corona that forms at the top of the shell. The corona develops when a high-voltage potential ionizes the air that surrounds a conductor, which is a normal condition. This condition is not an indication of leakage between the shell and the insulator.Inspect shell (3) 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 electrode (5) for excessive wear. Flat surfaces with sharp edges provide the best conditions for creating a spark. An electrode will become worn from use. The surfaces erode. A higher voltage is required to produce a spark.
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(6) Precious metal pads on the electrode and the ground strapCat spark plugs have precious metal pads (6) on the tips of the electrode and the ground strap. This material will gradually erode.Replace the spark plug if the precious metal is worn off.Light brown deposits or beige deposits around the electrode are 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. The buildup may cause a misfire. Large deposits may retain heat which can cause premature fuel ignition. Premature fuel ignition can lead to uncontrollable detonation.Cleaning the Spark Plug
Cleaning is not recommended for this spark plug.Installing the Spark Plug
Note: Use the 9U-7516 Spark Plug Gauge to measure the electrode gap. Do not use a flat feeler gauge for measuring the electrode gap of used spark plugs. A feeler gauge will produce a false measurement because the used precious metal surfaces will be curved.
Before installing the spark plug, set the electrode gap to 0.29 0.03 mm (.011 0.001 inch).Adjust the electrode gap by bending the ground electrode at the existing bend. Then bend the strap near the weld to achieve proper alignment and even spacing between the two precious metal surfaces. Measure the electrode gap after the alignment. Correct the electrode gap, if necessary.Note: Do not use anti-seize compound on spark plugs. Most of the heat is transferred through the threads and the seat area of the spark plug. The surfaces must be in contact to provide the heat transfer that is required.
Ensure that the spark plug is clean and free of dirt and oil.
Always use a new gasket when a spark plug is installed. If a used spark plug is installed, place a new 9Y-6792 Gasket on the spark plug. Orient the tabs of the gasket toward the electrode. Otherwise, the gasket may not seat properly. If a gasket for a spark plug is installed incorrectly, do not increase the torque on the spark plug to improve the seal. Do not reuse the gasket. Install a new gasket.
Do not overtighten