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4-134 L Engine Service Diagnosis - M38
4-134 L engine illustration shown for reference only - click here to shop these parts by interactive diagram
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| Service Diagnosis: | |
|---|---|
| Poor Fuel Economy | Ignition timing slow or spark advance stuck |
| Carburetor float high | |
| Accelerator Pump not properly adjusted | |
| High fuel pump pressure | |
| Fuel Leakage | |
| Leaky fuel pump diaphragm | |
| Loose engine mounting causing high fuel level in carburetor | |
| Low compression | |
| Valves sticking | |
| Spark plugs bad | |
| Spark plug cables bad | |
| Weak coil or condenser Improper valve tappet clearance | |
| Carburetor air cleaner dirty | |
| High oil level in air cleaner | |
| Dragging brakes | |
| Front wheels out of alignment | |
| Tires improperly inflated | |
| Inaccurate odometer | |
| Faulty fuel tank cap | |
| Clogged muffler or bent exhaust pipe | |
| Lack of Power | Low compression |
| Ignition system (Timing late) | |
| Improper functioning carburetor or fuel pump | |
| Fuel lines clogged | |
| Air cleaner restricted | |
| Engine temperature high | |
| Improper tappet clearance | |
| Sticking valves | |
| Valve timing late | |
| Leaky gaskets | |
| Muffler clogged | |
| Bent exhaust pipe | |
| Low Compression | Leaky valves |
| Poor piston ring seal | |
| Sticking valves | |
| Valve spring weak or broken | |
| Cylinder scored or worn | |
| Tappet clearance incorrect | |
| Piston clearance too large | |
| Leaky Cylinder head gasket | |
| Burned Valve and Seats | Sticking valves or too loose in guides |
| Improper timing | |
| Excessive carbon around valve head and seat overheating | |
| Valve spring weak or broken | |
| Valve tappet sticking | |
| Valve tappet clearance incorrect | |
| Clogged exhaust system | |
| Valves Sticking | Warped valve |
| Improper tappet clearance | |
| Carbonized or scored valve stems | |
| Insufficient clearance valve stem to guide | |
| Weak or broken valve spring | |
| Valve spring cocked | |
| Contaminated oil | |
| Overheating | Inoperative cooling system |
| Thermostat Inoperative | |
| Improper ignition timing Improper valve timing | |
| Excessive carbon accumulation | |
| Fan belt too loose | |
| Clogged muffler or bent exhaust pipe | |
| Oil system failure | |
| Scored or leaky piston rings | |
| Popping-Spitting-Detonation | Improper ignition |
| Improper carburetion | |
| Excessive carbon deposit in combustion chambers | |
| Poor valve seating | |
| Sticking valves | |
| Broken valve spring | |
| Tappets adjusted too close | |
| Spark plug electrodes burned | |
| Water or dirt in fuel | |
| Clogged lines | |
| Improper valve timing | |
| Excessive Oil Consumption | Piston rings stuck in grooves, worn or broken |
| Piston rings improperly fitted or weak | |
| Piston ring oil return holes clogged | |
| Excessive clearance, main and connecting rod bearings | |
| Oil leaks at gaskets or oil seals | |
| Excessive clearance, valve stem to valve guide (Intake) | |
| Cylinder bores scored, out-of-round or tapered | |
| Too much clearance, piston to cylinder bore | |
| Misaligned connecting rods | |
| High road speeds or temperature | |
| Crankcase ventilator not operating | |
| Bearing Failure | Crankshaft bearing journal out-of-round |
| Crankshaft bearing journal rough | |
| Lack of oil | |
| Oil leakage | |
| Dirty oil | |
| Low oil pressure or oil pump failure | |
| Drilled passages in crankcase or crankshaft clogged | |
| Oil screen dirty | |
| Connecting rod bent | |
* Learn more about the 4-134 L engine from the Master Parts List Manual for 50-52 M38