Electrical System - Gravely Convertible 10 Shop Manual

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Owner's manual (10 pages)

Table Of Contents

Table of Contents

projection on flywheel passes the trigger module, the flashlight tester should turn on, or if an ohmmeter is

used, a 5 to 10 ohm resistance should be indicated. Before being triggered, an open circuit should be

indicated. Replace the trigger module if wrong results are obtained from any of these tests.

AC Leads and Winding: If ignition trouble persists after the system checks out in each of the foregoing

tests, the AC leads or ignition windings are probably faulty. Replace stator assembly in this event.

Two basic types of electrical systems are in use on Kohler Single Cylinder Cylinder Engines. One system

involves the use of a motor-generator unit which functions as a starting motor and also as a DC generator for

charging the storage battery. The other system, the Magneto-Alternator System (also Breakerless-Alternator)

uses solid state electronic devices for converting Alternating Current to Direct Current for charging. The

charging and cranking circuit of the breakerless-alternator system is almost identical to that of the

magnetoalternator system -- the only difference is in the ignition coil or winding on the stator. A small

compact starter is used with the alternator systems. The major components of each system are:

MOTOR-GENERATOR SYSTEM

CHARGING CIRCUIT

Battery (12 volt)

Voltage (& Current) Regulator

Motor-Generator

CRANKING CIRCUIT

Motor-Generator

A 12 volt storage battery is used with both systems and can therefore be discussed separately. The

remainder of the components will have to be grouped according to the electrical system type.

BATTERY (All Models)

Storage batteries used are of the lead-acid type. Lead is used in the construction of the cellplates and

sulfuric acid serves as the electrolyte. "Wet" batteries are filled with electrolyte and are stored ready to use if

satisfactory charge has been maintained. With "dry charged" batteries, the plates are charged but an

electrolyte of specific grade must be added just before using. Both types function in the same general way.

All Kohler Engines use negative ground systems in which the negative ( - ) terminal of the battery is

connected in common ground to the engine while the positive ( + ) terminal is the "live" terminal. When

disconnecting battery always remove ground ( - ) terminal first.

Voltage Test: With a battery in good condition, each cell contributes approximately 1.95 to 2.08 volts. If less

than 0.05 volt difference is noted between the highest and lowest cells, the battery may be recharged. If the

difference is more than .05 volts, this could indicate a cracked plate or other damage which could call for

replacement of the battery.

Specific Gravity Test: As a battery discharges and the energy is not replenished, sulfuric acid is chemically

withdrawn from the electrolyte and lead sulfate deposits continue to build up on the plates. This results in a

diminishing specific gravity of the electrolyte. If the specific gravity drops below 1.240, the battery must be

recharged. In fully charged condition, the specific gravity will be in the 1.260 - 1.280 range. Hydrometer

readings must be corrected for variation in temperature of electrolyte. Add .004 to the reading for every 10°

above 80°F. and subtract .004 for every 100 below 80°F.

As a battery is recharged, a reverse chemical reaction takes place which causes the lead sulfate deposits to be

changed back to lead, lead dioxide and sulfuric acid. In effect, this reverses the discharge reaction and

restores materials to active condition. If sulfate deposits become too great or if the level of the electrolyte is

not maintained above the level of the plates, the battery may be permanently damaged.

Safety Precautions: Adequate ventilation must be provided when batteries are being recharged. Also, sparks,

open flames and smoking should be avoided since hydrogen gas is produced which, if ignited, can cause an

internal explosion that can shatter the battery. This gas is produced in quantity only while the battery receives

high rate of charge but can linger for several hours in a poorly ventilated area.

Service: To maintain battery in top condition perform services at frequent intervals: