Kohler LH630-775 Service Manual page 23

Section 3
Troubleshooting
Engine Overheats
1. Radiator, and/or cooling system components
clogged, restricted, or leaking.
2. Excessive engine load.
3. Low crankcase oil level.
4. Low cooling system fluid level.
5. High crankcase oil level.
6. Lean fuel mixture.
7. Fan belt failed/off.
8. Cooling fan broken.
9. Water pump belt failed/broken.
10. Water pump malfunction.
11. Faulty carburetor.
Engine Knocks
1. Excessive engine load.
2. Low crankcase oil level.
3. Old or improper fuel.
4. Internal wear or damage.
5. Hydraulic lifter malfunction.
6. Quality of fuel.
7. Incorrect grade of oil.
Engine Loses Power
1. Low crankcase oil level.
2. High crankcase oil level.
3. Dirty air cleaner element.
4. Dirt or water in the fuel system.
5. Excessive engine load.
6. Engine overheated. (See "Engine Overheats")
7. Faulty spark plugs.
8. Low compression.
9. Exhaust restriction.
10. Low battery.
11. Incorrect governor setting.
Engine Uses Excessive Amount Of Oil
1. Incorrect oil viscosity/type.
2. Clogged or improperly assembled breather.
3. Breather reed broken.
4. Worn or broken piston rings.
5. Worn cylinder bore.
6. Worn valve stems or valve guides.
7. Crankcase overfilled.
8. Blow head gasket/overtightened.
Oil Leaks from Oil Seals, Gaskets
1. Crankcase breather is clogged or inoperative.
2. Breather read broken.
3. Loose or improperly torqued fasteners.
4. Piston blowby or leaky valves.
5. Restricted exhaust.
3.2
Engine Loses or Uses Coolant
1. Overheating-See "Engine Overheats".
2. External leakage-from a joint connection, or a
component of the cooling system.
3. Internal leakage-from a head gasket, or cooling
system water jacket (passage) leak.
External Engine Inspection
Before cleaning or disassembling the engine, make a
thorough inspection of its external appearance and
condition. This inspection can give clues to what might
be found inside the engine (and the cause) when it is
disassembled.
• Check for buildup of dirt and debris on the
radiator, crankcase, cooling system components,
and other external surfaces. Dirt or debris on these
areas are causes of higher operating temperatures
and overheating.
• Check for obvious fuel, oil, and coolant leaks, or
damaged components. Excessive oil leakage can
indicate a clogged or improperly assembled
breather, worn or damaged seals and gaskets, or
loose or improperly torqued fasteners. Coolant
leaks can cause higher operating temperatures and
overheating.
• Check the air cleaner assembly/components for
damage or indications of leakage.
• Check the air cleaner element and inner element.
Look for holes, tears, cracked/damaged sealing
surfaces, or other damage that could allow
unfiltered air into the engine. Also note if the
elements are dirty or clogged. These could
indicate that the engine has been underserviced.
• Check the carburetor throat for dirt. Dirt in the
throat is further indication that the air cleaner is
not functioning properly.
• Check the oil level. Note if the oil level is within
the operating range on the dipstick, or if it is low
or overfilled.
• Check the coolant level within the reservoir and in
the radiator. A low or improperly filled cooling
system can cause overheating, excessive fuel
consumption, and a lack of power.