Husqvarna 966451906 Assembling the piston and cylinder, Carbon build-up B, Piston ring breakage

Page 47

Repair Instructions

Faults and causes

Score marks on the piston (A)

1. Leakage, check not carried out.

2. Too low octane fuel.

3. Too low or incorrect oil in the fuel.

Carbon build-up (B)

1. Too much or incorrect oil in the fuel. See Figure 63.

Piston ring breakage

1. Piston ring worn out.

2. Oversized piston ring groove.

AB

Fig 63

7.22 Assembling the piston and cylinder

1

Oil the gudgeon pin bearing with two-stroke oil and insert it into the crank rod. See figure 64.

2

Replace the piston with the arrow facing the ex- haust port, and slide in the gudgeon pin and fit the circlips. NOTE! Use new circlips. See figure 64.

3

Oil the piston and piston ring with two-stroke oil.

4

Put a new cylinder base gasket in place. Compress the piston ring and carefully push the piston into the cylinder opening.

5

Attach the cylinder. The screws must be tightened crosswise with a tightening torque of 8-10 Nm.

NOTE!

It is very important that the intake system is sealed. Otherwise the engine may seize up.

Fig 64

Fig 65

English - 47

Image 47
Contents 562XP/XPG Page Contents Index Vibration damping system Contents Introduction and safety regulationsIntroduction and safety instructions Special Instructions General InstructionsSymbols in the Workshop Manual Symbols on the sawTechnical data NGK CMR6H 12b Service tools12a 13d 13a 13b 13c Key Service dataEnglish Contents Safety equipmentAlt Cleaning and inspectionDismantling the chain brake Assembling the chain brake Do not touch the muffler until it has cooled. Risk of burns Dismantling the mufflerAssembling the muffler Functional inspectionDismantling the start/stop control Replacing the chain catcherResistance test stop function Assembling the start/stop controlCleaning and inspection Safety equipment Repair instructions Dismantling the starter Cleaning and inspection Clean the parts and checkWear protective glasses Replacing a broken or worn starter cordTensioning the return spring Replacing a broken return spring Starter assemblyDismantling the ignition module and flywheel Assembling the ignition module and flywheel Min 60 mm Dismantling the centrifugal clutchDismantling the oil pump and screen Assembly of centrifugal clutchDismantling the intake system Assembling the oil pump and screenAssembling the intake system Design CarburettorFunction Dismantling the carburettor English Assembly Cleaning and inspection Clean all units in clean petrolEnglish Fitting on the saw Pressure testing the carburettorMake sure that the following components are correctly fitted Opening pressure inwards Tank unitVenting the fuel tank Test Opening pressure outwardsVibration damping system Dismantle Replacing the fuel filterReplacing the fuel hose/return hose Replacing the fuel pump PurgeDismantling the piston and cylinder English Piston ring breakage Faults and causes Score marks on the piston aAssembling the piston and cylinder Carbon build-up BLoosen Pressure testing the cylinderDismantling the crankshaft and crankcase Page Repair Instructions Sealing rings Assembling a complete crankshaft Replacing a bar bolt with intact crankcase Repairing damaged threadsReplacing the bar bolt English Troubleshooting Idling low speed TroubleshootingStarting Acceleration and retardation Troubleshooting methodsHigh speed 2011W31 115 26