Case Compact Tractor T90

Remove the wire from the spark plug and use a thin wall deep socket spark plug type wrench of correct size 13/16" to remove the spark plug.

The wrong size or type socket wrench can cause distortion or insulator breakage.

The first thing to inspect after removal of a plug is the copper gasket. This will tell you if the spark plug was installed correctly.

A Spark plug that has been properly torqued in place to 27 foot pounds will have the copper gasket compressed to 1/2 of its original thickness.

A Spark plug gasket that was not compressed enough when the plug was installed can cause compression leakage. The plug will run hotter then it should as the heat will not be transferred from the plug to the cylinder head as fast.

A Spark plug gasket that is compressed too much when the plug is installed will cause the plug to run colder then it should and thus will foul a lot faster. It is also possible that when the plug is installed too tight, it will cause distortion of the electrodes. Thus the plug gap would be increased beyond its original setting.;

Warning: This procedure requires trained personnel with PPE!

Abrasive type cleaning machine available?

If abrasive type cleaning machine is not available, report to the maintenance team and stop the procedure

Electrode sparking areas filed to obtain bright flat parallel surfaces?

Plug washed in a good cleaning solvent and blown dry with air pressure?

Gap between the electrodes (in inches)

Set the gap by bending the ground or outside electrode, never try to bend the center electrode as the insulator will crack.

NOTE: On Spark Ignition engines remove the center coil wire to prevent engine from starting

Connect a volt meter (12 volt) between the positive and negative terminals of the battery, Figure F-5

Crank the engine for 15 seconds and record voltage

Connect voltmeter (12 volt) between the starter generator 'A' terminal and ground on starter generator frame, Figure F-5

Crank the engine and record voltage

If voltage is not the same or varies more than .5 volt, check the battery cables, clean and tighten connections

Sign off on the battery cranking voltage test

Warning: This procedure requires trained personnel with PPE!

IMPORTANT: Under no circumstances should a pry bar be used on the starter - generator to obtain belt tension, as damage to the bearings could result.

Check for excessive looseness and wear of the belt

Enter the belt tension (should be depressed 1/4 inch between the pulleys)

Sign off on the belt adjustment

Warning: This procedure requires trained personnel with PPE!

Enter the temperature of the solution

Note: Hydrometer reading is only correct when the temperature of the solution is 80° F.

Note: If the temperature is above or below 80° F, correct the reading by adding .004 gravity points for every 10° above 80°F. or subtracting .004 gravity points for every 10° below 80° F.

Enter the corrected hydrometer reading

Note: If the specific gravity readings between the cells show a variation of .025, the battery should be replaced.

Enter the specific gravity reading of the cells

Note: The battery should never be allowed to drop below 75% charge while not in use.