LONCIN G250F Service Manual
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LONCIN G250F Service Manual

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SERVICE MANUAL
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Summary of Contents for LONCIN G250F

  • Page 1 SERVICE MANUAL （ ） （ ）...
  • Page 2 Preface PREFACE This manual covers construction, function and servicing procedures of the G250F(D)S snow engine Careful observance of the CONTENTS instruction given herein will result in better, safer service work. Safety and General Information Due to product improving, we can change Specification specification ；...

  • Page 3: Table Of Contents

    Section 1 Safety and General Information 1、Safety and General Information 1.1 General safety --------------------------------------------------1－2 1.2 Service rules ----------------------------------------------------1－3 1.3 Serial number location ----------------------------------------1－4 1.4 Oil Recommendations ----------------------------------------1－5 1.5 Torque values AND Other Detail Specs ------------------1－5 1.6 Maintenance standards---------------------------------------1－7 1.7 Troubleshooting ------------------------------------------------1－8 1.8 Special tool ------------------------------------------------------1－11...

  • Page 4: Section 1 Safety And General Information

    Section 1 Safety and General Information Section 1 Safety and General Information Safety Precautions To ensure safe operation please read the following statements and understand their meaning. Also refer to your equipment manufacturer's manual for other important safety information. This manual contains safety precautions which are explained below. Please read carefully.

  • Page 5: Service Rules

    Section 1 Safety and General Information 1.2 Service rules 1. Use genuine LONCIN or LONCIN- 4. When screwing bolts or nuts, begin with recommended parts and lubrication oil. larger-diameter inner bolt first, and Parts that don’t meet design specifications tighten to the specified torque diagonally may damage the device or engine.

  • Page 6: Serial Number Location

    1.3 Serial number location The serial number on stamped on the crankcase, as shown on the following drawing when inquiring about engine or ordering parts in order to get correct parts for the unit being serviced by LONCIN INDUSTRIAL CO., Ltd’s dealer...

  • Page 7: Oil Recommendations

    Section 1 Safety and General Information 1.4 Oil Recommendations When the ambient temperature is under -25℃～-30℃, SAE 0W-30/40 is recommended for general use; when the ambient temperature is above -25℃ but under 4.4℃, SAE 5W-30 or 0W30/40 is recommended for general use. The SA oil viscosity and service classification are in the API label on the oil container.
  • Page 8 Section 1 Safety and General Information Breather Chamber Bolt M5×10 8～12 Ignition Coil Bolts M6×25 8～12 Starter Bolt M6×12 8～12 Recoil Start Bolts M6×8 8～12 Control Assy Bolt M6×8 8～12 Starter Motor Bolt M6×35 8～12 Governor Arm Nut 8～12 Air cleaner Nuts 8～12 Protector Muffler Bolts M6×12...

  • Page 9: Maintenance Standards

    Section 1 Safety and General Information 1.6 Maintenance standards Unspecified unit : mm Standard Service Limit Part Item G250F(D)S 3300±100 Engine Maximum speed（rpm/min） cylinder Sleeve(inside diameter) 75.17 skirt outside diameter 74.97 74.82 Clearance to cylinder 0.015-0.05 0.12 piston Piston pin bore inside diameter 18.002...

  • Page 10: Troubleshooting

    Section 1 Safety and General Information 1.7 Troubleshooting a. Possible cause Incorrect oil make Primer pump or primer pump hose damage Carburetor trouble Starting trouble Wrong igniter coil gap temperature Unstable RPM and pre-fire Igniter coil trouble Spark plug trouble High speed abnormal Governor adjusting improper Wrong valve gap...
  • Page 11 Section 1 Safety and General Information 5. Inspecting cylinder pressure: Pressure Check valve gap if correct. Put the pressure meter on the insufficient. Check cylinder cover spark plug hole and pull starter, tightened. check pressure. Check combustion chamber if damaged. Check pad, valve or valve 6.
  • Page 12 Section 1 Safety and General Information Checking spark 1) Remove spark plug 2) Put the spark plug on the spark cap 3) Connect (－) electrode of the spark plug（thread）to grounding, pull starter to check if there is spark at the electrode joint. WARNING Don’t grab spark terminal by wet hand spark plug...

  • Page 13: Special Tool

    Section 1 Safety and General Information 1.8 Special tool Ser. Description Note Driver lever，40 mm 6、7、8 lever 42×47 mm outside retainer 6204 bearing assembly 52×55 mm outside retainer driver 6205、62/22 bearing assembly 30 mm inside retainer driver timing gear 35 mm inside retainer driver governor driving gear assembly 22 mm assistant driver 62/22 bearing assembly...
  • Page 14 Section 2 Specifications 2、Specifications 2.1 Parameter ---------------------------------------------------------2－2 2.2 Dimensional drawings ------------------------------------------2－4 2.3 P.T.O Dimensional drawings ----------------------------------2－5...
  • Page 15 Section 2 Specifications Specifications Section 2 2.1 Parameter LONCIN SNOW ENGINE SPECIFICATION MODEL G250F(D)S ENGINE TYPE SINGLE CYLINDER, 4-STROKE, FORCED AIR COOLING, OHV25° DISPLACEMENT(cc) Bore×Stroke(mm) 75×57 COMPRESSION RATIO 8.5：1 MAX.POWER（KW) MAX.TORQUE（N.m/rpm) 15.6/2600 No LOAD SPEED（rpm） 3300±100 OIL CAPACITY( L) FUEL CAPACITY (L) ≤375...
  • Page 16 STARTER RECOIL AT 8 O'CLOCK POSITION FUEL TANK MANUAL CLICK-CLICK FLYWHEEL WITH RING GEAR OIL SEAL AIR CLEANER WITHOUT FILTER CYLINDER Shield ADDED SHIELD MUFFLER STANDARD WITH GUARD ENGINE KILL SWITCH KILL SWITH DECALS EPA/CARB DECAL, LONCIN LOGO, EXTRA ONE...
  • Page 17 Section 2 Specifications 2.2 Dimensional drawings G250F(D)S...
  • Page 18 Section 3 Maintenance 2.3 P.T.O Dimensional drawings B4轴 / Type B4...
  • Page 19 Section 3 Maintenance 3、Maintenance 3.1 Maintenance schedule ---------------------------------------3－2 3.2 Engine oil --------------------------------------------------------3－2 3.3 Spark plug -------------------------------------------------------3－4 3.4 Valve clearance ------------------------------------------------3－5 3.5 Governor ---------------------------------------------------------3－6 3.6 Fuel filter -------------------------------------------------------- 3－7...

  • Page 20: Maintenance

    Section 3 Maintenance Maintenance Section 3 3.1 Maintenance schedule REGULAR SERVICE PERIOD Performed at every indicated month or First Every 3 Every 6 Every Each operating hour interval, whichever comes month or months or months or year or first. 20 Hrs. 50 Hrs.
  • Page 21 Section 3 Maintenance 3. Refill the engine with the correct amount of the recommended oil. Engine oil capacities: 0.7 L Use a high-detergent, premium quality 4-stroke engineoil certified to meet or exceed US.Automobile manufacturers’ requirements for API Service Classification SG, SF.SAE 5W-30 or 0W-30(at different ambient temperatures) is recommended for general, all-temperature use.

  • Page 22: Spark Plug

    Section 3 Maintenance 3.3 Spark plug Recommended types: F7RTC NOTICE Spark plugs of the wrong size or incorrect heat range can cause engine damage. 1. Disconnect the spark plug cap and remove any dirt from around the spark plug area. 2.

  • Page 23: Valve Clearance

    Section 3 Maintenance 3.4 Valve clearance Bolt Sealing Valve clearance inspection and adjustment must be done with the engine cold. Remove the cylinder head cover, and set the piston at top dead center of the compression stroke (both valves will be fully closed). Cover 1.

  • Page 24: Governor

    Section 3 Maintenance 3.5 Governor 1.Loosen the governor bracket nut, wave the bracket to make throttle full open. 2.Turn the governor arm right to make governor full closed ( same direction with throttle full open), tighten the nut。 3.Check governor arm and throttle if moving freely, 4.Start engine, and allow it to warm up to the normal operating temperature.

  • Page 25: Fuel Filter

    Section 3 Maintenance 3.6 Fuel filter Fuel cap WARNING Gasoline is extremely flammable and explosive. Don’t smoke and fire on the Fuel tank working site.Don’t allow the gasoline overflowing. 1.Drain the fuel in the fuel tank thoroughly out and remove the fuel tank. 2.Remove the fuel tube, and remove filter from the fuel tank.
  • Page 26 Section 4 Disassembly and service 4. Disassembly and service Drain Bolt ---------------------------------------------------------------4－2 Control box bracket --------------------------------------------------4－3 Fuel tank ----------------------------------------------------------------4－4 Muffler -------------------------------------------------------------------4－5 Air Cleaner -------------------------------------------------------------4－6 Carburetor --------------------------------------------------------------4－7 Engine cover 1#-------------------------------------------------------4－10 Governor bracket and throttle control assy --------------------4－11 Recoil starter----------------------------------------------------------4－12 4.10 Flywheel, ignition coil ---------------------------------------------4－15 4.11 Cylinder head &...

  • Page 27: Disassembly And Service

    Section 4 Disassembly and service Section 4 Disassembly and service 4.1 DRAIN BOLT Disassembly/Reassembly OIL EXTENSION ROD × × FLAT WASHERφ10 × × BOLT: M10 1.25 TORQUE: 22～25N.m...

  • Page 28: Control Box Bracket

    Section 4 Disassembly and service 4.2 CONTROL BOX BRACKET Disassembly/Reassembly SCREW BOLT M4×55 (2) BOLTt: M6×20 TORQUE: (8~12)N•m FLAT WASHER (2) ELCETRIC STARTING BOX HOLDER...

  • Page 29: Fuel Tank

    Section 4 Disassembly and service 4.3 FUEL TANK Disassembly/Reassembly WARNING Drain the fuel tank and fuel Fuel tank tube fuel thoroughly out before Fuel tank capability: 3.0L disassembling. Fuel vapor or Assembly:Clean dirt ants spilled gasoline may ignite. thoroughly before assembling Bolt: M6×20（3）...

  • Page 30: Muffler

    Section 4 Disassembly and service 4.4 Muffler Disassembly/Reassembly Bolt: M6×12, Protector Muffler Torque: (8~12)N•m Body Muffler Assembling: Lightly with plastic hammer to remove dirt, then, assemble. Muffler,protect bracket Plate Nuts: M8, (2) Torque: (27~30) N•m Muffler Pad...

  • Page 31: Air Cleaner

    Section 4 Disassembly and service 4.5 Air cleaner Disassembly/Reassembly Disassembly/assembly When disassembling and assembling, choke will turn and fuel valve switch off. CLIP Nuts: M6, (2) Torque: (8~12) N•m Air Box Seat Switch ,Engine Stop Air Heat Box Key Switch Stop...

  • Page 32: Carburetor

    Section 4 Disassembly and service 4.6 Carburetor a、Disassembly/Reassembly WARNING Loosen the drain bolt and drain the carburetor before disassembling. Fuel vapor or spilled fuel may ignite. Fuel tube Assembly: Check for no crack or aged before assembling, if necessary, please replace. Insulating pad COLLAR Assembling:...
  • Page 33 Section 4 Disassembly and service Disassembly/Reassembly Note：Clean the carburetor before disassembling. Assistant jet Assembly: Clean with compressed air and lightly lubricate 0-ring before O-ring assembling. Choke valve handle Air pump Primer Primer Line Clip, (2) Float valve Body Carburetor Main nozzle Assembly: Assemble after checking for float seat, Assembly:...
  • Page 34 Section 4 Disassembly and service c、Inspecting float height Place the carburetor as shown on the drawing. Measure the distance between the float top and carburetor body when the float just contacts the float valve Standard height 13.7 mm If the float height is not within specification, replace float valve and recheck the float height Washing carburetor WARNING...

  • Page 35: Engine Cover 1

    Section 4 Disassembly and service 4.7 Engine cover Disassembly/Reassembly Fuel tube Assembly: Check for no crack or aged before assembling, if necessary, please replace. Engine cover Safeguard tube Fuel Swtich Knob,Fuel Swtich Screw: M4×18 Nut:M6 Torque: (8~12)N•m 4-10...

  • Page 36: Governor Bracket And Throttle Control Assy

    Section 4 Disassembly and service 4.8 Governor bracket and throttle control assy Disassembly/Reassembly Governor spring Throttle reset spring Assembly: Put long end of Assembly: Insert hook onto control lever Governor Rod long end of hook onto lever. Engine switch Bolt Quadrate Head Nuts: M6 Governor Arm CONTROL ASSY...

  • Page 37: Recoil Starter

    Section 4 Disassembly and service 4.9 Recoil starter a、Disassembly/Reassembly Recoil starter Reassembly: WARNING Remove dirt debris Wear gloves and eye protectors. before installation. Don’t let the spring out when disassembling. The installation direction can be changed by changing the relative positions of the holes in recoil starter case.
  • Page 38 Section 4 Disassembly and service b、Recoil starter assembly WARNING Wear gloves and eye protectors. Don’t let the spring out when disassembling. Insert the hook on the outer side of the scroll spring into the hole of the starter Pass the rope through the hole of the starter wheel and tie the end of rope (shown on drawing ), wind the rope onto the reel in the arrowed direction , and remain about 30cm outside the starter wheel.
  • Page 39 Section 4 Disassembly and service Pass the starter rope through the starter tray, and tie as shown as drawing. WARNING Don’t allow the starter wheel leaving off the starter tray, otherwise, the spring fly out to injure person. Assemble the pawl and friction spring together on the starter wheel, tighten the bolt of bolt.

  • Page 40: Flywheel, Ignition Coil

    Section 4 Disassembly and service 4.10 Flywheel, ignition coil Flywheel <Starting motor> a、Disassembly/Reassembly . Remove the igniting coil before Starting motor type: removing flywheel Start the motor, and measure motor . Don’t hit the flywheel with a operation performance, if the operation hammer.
  • Page 41 Section 4 Disassembly and service b、 Igniting coil gap adjustment When reassembling igniting coil, adjust the igniting coil gap. 1) Lightly tighten the igniting coil mounting bolt. 2) Insert the feeler gauge or a piece of paper of the same thickness between the flywheel and coil as shown.
  • Page 42 Section 4 Disassembly and service c、 Spark plug cap Put the tester to contact the two end of the spark plug cap and measure spark plug cap resistance Resistance 4.5-5.5 KΩ If the resistance is out of the specification, replace the spark plug. Spark plug cap Adjustment Adjustment is required only when the ignition coil or the flywheel has been removed.

  • Page 43: Cylinder Head & Valves

    Section 4 Disassembly and service 4.11 Cylinder head & valves Disassembly/reassembly Bolt: M6×16, (4) Torque: (8~14)N•m Cylinder pad Cylinder Head Cover Pad Pin (2) Cylinder head Bolt: M10×65, (4) . Remove carbon deposits from Torque: (32~35)N•m the combustion chamber and Removal/Installation check the valve seat before Loosen and tighten the...
  • Page 44 Section 4 Disassembly and service Disassembly / reassembly Spark plug Valve spring retainer(2) Intake valve Assembly: Don’t interchange Disassembly: Push down spring Reassembly: retainer and move the retainer to the small the exhaust and intake valves. Clean and adjust spark hole so that the valve stem slips through plug before installation.
  • Page 45 Section 4 Disassembly and service Valve spring free length Measure the free length of the valve springs. Standard Service limit 34~35 mm 32.5 mm Replace the spring if they shorter than the service limit. Valve seat width Remove carbon deposits from the combustion chamber.
  • Page 46 Section 4 Disassembly and service Stem –to- guide clearance Subtract each valve stem OD from the corresponding guide ID to obtain the guide-to-stem clearance. Standard Service limit 0.02-0.044 mm 0.10 mm 0.06-0.084 mm 0.12 mm If the stem-to-guide clearance exceeds the service limit, determine if the new guide with standard dimensions would bring the clearance within tolerance.
  • Page 47 Section 4 Disassembly and service 5. install the new valve guide from the valve spring side of the cylinder head. Drive the valve guide until the clip is fully seated as shown. 6. after installation, inspect the valve guide for damage.
  • Page 48 Section 4 Disassembly and service material from the bottom edge. Bu sure that the width of the finished valve seat is within specification. Valve seat width Standard Service limit 0.8 mm (0.03 in) 2.0 mm (0.08) 1. make a light pass with the 45° cutter to remove any possible burrs at the edges of the seat.

  • Page 49: Crankshaft / Piston / Camshaft

    Section 4 Disassembly and service 4.12 Crankshaft / piston / camshaft Disassembly / reassembly Crankshaft Assembly: Insert until the bearing contacts crankshaft, be careful not to damage Oil filler cap Crankcase Cover Gasket oil sealing. Packing,Oil Filler Crankcase cover Governor driving gear Oil sealing Timing gear Connecting rod cover...
  • Page 50 Section 4 Disassembly and service Crankshaft bearing Assembly： Assemble the bearing in with following the tool after applying engine oil. Assembly lever 52×55 mm outer retainer assembler Assistant assembler Gear on the crankshaft Disassembly： Mark a line on the crankshaft and a timing gear. Set the commercial available bearing puller plate on the lower part to the governor drive gear and remove the crankshaft and timing gear by manual...
  • Page 51 Section 4 Disassembly and service Disassembly / reassembly Piston connecting rod Assembly: . Put the piston ring sign facing up when Piston Rotation Arrow assembling. Second Ring . Don’t wrongly assemble the top ring and the First ring Second Ring Open second ring.
  • Page 52 Inspection Piston pin OD Model Standard Service limit G250F(D)S 18.0 mm 17.954 mm Cylinder inside diameter Measure three points on the “X” and “Y” shaft and record cylinder inside diameter（“X” shaft is vertical to crankshaft and “Y”...
  • Page 53 Before measuring end gap, use the piston top to position the ring so it will not be cocked in the cylinder bore. Piston pin hole ID Model Standard Service limit G250F(D)S 18.002mm 18.048 mm Piston pin to Piston hole gap Standard Service limit 0.002-0.014 mm...
  • Page 54 Section 4 Disassembly and service Connecting rod small end ID Model Standard Service limit G250F(D)S 18.006-18.017 mm 18.07 mm Connecting rod big end ID Original size Standard Service limit 30. 22~30.233 mm 30.274 mm Crankshaft pin OD Standard Service limit 29.975~29.99 mm...
  • Page 55 Section 4 Disassembly and service Do not rotate the crankshaft while the tightening connecting rod bolt 3) Remove the connecting rod and measure the plastic gauge. Standard Service limit 0.040-0.063 mm 0.12 mm 4) If the clearance exceeds the service limit, replace the connecting rod and recheck the clearance.

  • Page 56: Governor

    Section 4 Disassembly and service 4.13 Governor Disassembly / reassembly Governor nylon gear Assembly: . Check the gear for no worn and Split pin damaged before assembling. Assembly: . Check if governor flyweight has . Immediately fit the split pin after been assembled before assembling assembling governor arm and move crankshaft.
  • Page 57 Section 4 Disassembly and service LONCIN MOTOR CO.,Ltd. Add: No.99 Hualong Road,Jiulongpo District,Chongqing,China Tel: 86 23 8906 7577/7599 Fax: 86 23 8906 7533 隆鑫通用动力股份有限公司 地址：重庆市九龙坡区华龙大道 99 号 电话：86 23 8906 7577/7599 传真：86 23 8906 7533 Web site: www.loncinengine.com E-Mail: marketing@loncinengine.com...

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G250dG250s

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