Roth 9 th Ch 14 Elect. System Service Pages 245 276
1. is the term used to describe periodic, preventative maintenance done to the ignition system of any engine. It may often times also include fuel system, air filter, and valve service. Brush up Tune up Soup up
2. The ignition system will produce only as much voltage as is needed to jump the gap, (usually 12 kv) although it has the capability to produce as much as 30 kilovolts if needed. Spark Plug Breaker Point PTO Switch
3. It takes more to fire a spark across the electrode gap of a used plug than a new one. Resistance Voltage Capacitance
4. You can analyze the quality of combustion that has been taking place by examining the deposits on the spark plug. NOTE: Beige to gray tan deposits are a sign of normal burning. Carbon Checking Savings
5. Allow the engine to before removing spark plugs from aluminum cylinder heads. Use a slight amount of anti seize compound on the threads when reinstalling the spark plug. Heat up Cool Rest
6. spark plugs by abrasive blasting is not recommended by any engine manufacturer! Cleaning Swabbing Removing
7. Always use a feeler gauge for gapping spark plugs, especially used ones. Wire Flat Brass
8. Either a seat or a compressible, metal is used to seal spark plugs against the metal of the cylinder head. NOTE: Threads have no compression sealing ability of their own. Tapered, Gasket Threaded, O Ring Washer, Dryer
9. Spark plugs should be tightened into aluminum cylinder heads at a torque of to inch pounds, which is the same as 13 to 15 foot pounds. Ft. Lbs. x 12 = in. Lbs. In. Lbs. 12 = Ft. Lbs. 300 500 30 50 156 180
10. air gap should be adjusted with a non magnetic (paper or plastic), flat feeler gauge located between the coil laminations and the flywheel magnet. External coil engines only. Armature Crankshaft Contact Point
11. Either a flywheel or a off tool should be used to properly loosen and remove the flywheel from the crankshaft taper. Puller, Knock off Torquer, Knock off Slammer, Knock off
12. If a flywheel key is sheared to the right (clockwise) of the, the flywheel nut was tight but the crankshaft was stopped abruptly. If the key is sheared to the left of the keyway, the situation was likely caused by a loose or under torqued flywheel nut. (Always check for a bent crankshaft if the key is sheared!) Key Way Key Seat Key Slot
13. A sheared flywheel will cause a no spark condition on an engine with breaker point ignition. The same problem on an electronic ignition system will allow a spark, but the timing will be so far off the engine will not start. Sheared right = advanced timing & kickback. Sheared left = late timing & loss of power. Fin Key Nut
14. Ignition coil windings usually have between.5 to 5 ohms of resistance. (low volts/low ohms) Charging Primary Secondary
15. Ignition coil windings usually have between 500 to 15,000 ohms of resistance due to excessive length & small cross sectional diameter of their copper conductors. (high volts/high ohms) Charging Primary Secondary
16. can be checked w/ an ohmmeter or a DMM w/ a micro farad capacitance scale. Condensers Points Plugs
17. After installing and gapping breaker points, they should be cleaned by pulling paper through them while spring loaded in the closed position. Typical point gap is.020. Toilet Lint free Ph
18. Most ignition sparks are timed to happen a little BTDC. Some are adjustable by setting the piston height to specs & rotating the stator until the just break open. (loss of continuity/beep) Early spark timing causes kick back during starting. Late spark timing causes lack of power & high HC emissions. Condensers Points Plugs
19. While adjusting the timing, piston height can be set to specs with a indicator, depth, flat feeler gauge, dial caliper (depth end) or a special graduated rod, timing tool. Dial, Micrometer Electronic, Dial Dial, Outside
20. A wrench should be used to hold the flywheel during torquing to prevent fin damage. Streak Strap Serpentine
21. An alternative to using a strap wrench is to fill the cylinder with nylon and then rotate the crankshaft squeezing the rope between the piston and the cylinder head. This stops crank rotation. stockings rope washers
22. Whenever a gasket has been tightened, the engine operated, and then re loosened, it should be replaced unless it is the type with a graphite coating they are a little more forgiving. Head Breather Sump Cover
23. The CPSC requires an system on rotary lawn mower applications. It is mandated that all blades or PTO s be stopped within 3 seconds of the operator not being present. Blade Stop Operator Presence Ignition Stop
24. Implements may need more than 1 ignition or cut out switch to meet CPSC requirements. Interlock Key Toggle
A primary ignition circuit stop switch is typically parallel wired causing a short to ground. An interlock switch to prevent cranking is typically series wired causing an open circuit.
25. A is a tool used to determine the specific gravity (density) of battery electrolyte. Battery electrolyte is typically 36% sulfuric acid and 64% water. (1.280 = full charge) Dipstick Hydrometer Carbon Pile
26.The cranking power of lead acid batteries is reduced in temperatures. Low or Cold Medium High or Hot
27. The larger the American standard gage number of a wire, the in diameter it is. Larger Smaller
28. A is a heavy duty, electromagnetic switch used to route large amounts of amps to starters with only small amounts of current through the ignition switch. Relays are similar but smaller. Solenoid Motor Modulator
29. Fuel shutdown solenoids that close the carburetor main jet are also known as solenoids. They prevent the loud pop in the muffler after shutting off a hot engine. Anti After Fire Anti Aircraft Fire Anti Back Fire
30. Use a DMM to check for voltage in wiring & connections that prevent a starter from cranking. Available Drops Shorts
31. A simple is made of stator windings, flywheel magnets, & a or a rectifier bridge which changes AC to DC for battery charging and lighting operation. Alternator, Diode Starter, Rectifier Module, Transistor
32. An circuit has no continuity. Open Short High Resistance
32. A coil of wire has less resistance than specifications. Open Shorted Grounded
32. A circuit with high limits amps going to the consumer. Volts Amps Resistance
32. A circuit shorted to has a path to either body, frame, or engine sooner than desired. Hot or Power Ground Hockey Sticks
32. A circuit shorted to has a path to a source, like the battery, sooner than desired. If the ignition switch is closed & the neutral safety switch is closed, the relay passes electricity to the starter solenoid. When the relay is energized, the solenoid is pulled shut & the motor turns. Question Where could a short to hot occur that would continuously crank the starter motor? Hot or Power Ground Hockey Sticks