Stihl Carburetor Service Repair Manual

Stihl Carburetor Service Repair Manual diagrams

Stihl Carburetor Repair Guide With Diagrams

Stihl Carburetor Service Repair Manual for the repair proceedures of most Stihl Carburetors. The manual is available as a full PDF download, containing clear diagrams and accurate repair and tuning information that is suitable for most Stihl carburetors.

Stihl Carburetor Service Repair Manual Contents

1. Safety Precautions 2
2. Introduction 2
3. Assignment 3
3.1 Designation 8
4. Purpose of Carburetor 8
5. Construction/Function 9
5.1 Fuel Pump 9
5.2 Operating Conditions 11
5.2.1 Full Load 11
5.2.2 Idle 12
5.2.3 Carburetor with Fixed Idle Jet and Primary Mixture Control 14
5.2.4 Carburetor with Balanced Idle System (Fixed Idle Jet and Air Bypass System) 15
5.2.5 Part Load 16
5.3 Problematic Operating Conditions 17
5.3.1 Starting 17
5.3.2 Temperatures/Humidity 19
5.3.3 Acceleration 19
5.3.4 Dirty Air Filter/Compensator 20
5.4 Special Features 21
6. Troubleshooting Chart 23

7. Servicing 25
7.1 Leakage Test 25
7.2 Cleaning 25
7.3 Pump Diaphragm 26
7.4 Metering Diaphragm 26
7.5 Inlet Needle 27
7.6 Main Jet 28
7.7 Full-Load Fixed Jet/Part-Load Fixed Jet 29
7.8 Control Valve 29
7.9 Manual Fuel Pump 30
7.10 Check Valve 30
7.11 Carburetor Body 31
7.12 Throttle Shaft 32
7.13 Choke Shaft 34
7.14 Accelerator Pump 35
7.15 Lever Mechanism on Carburetors with Automatic Choke 36
7.15.1 Throttle Shaft/ Choke Shaft 38
7.16 HL-324A / HL-327D / LA-S8A Carburetors 38
7.16.1 Throttle Shaft 43
7.16.2 Choke Shaft 44
7.17 WYL-63 / WYL-73 Rotary Valve
Carburetors 45
7.18 Standard Setting on Walbro Carburetors 50
7.18.1 WT-283B, WT-323, WT-325A, WT-326C,
WT-360, WT-396, WT-403A, WT-493, WT-498A, WT-503 Fixed Jet Carburetors 50
7.18.2 HD-13A, HD-16, HD-17, HD-18A, HD-21A, HD-22, WY-69, WT-329, WT-330, WT-367, WT-393, WT-489, WT-492, WJ-69 Carburetors with Limiter Caps 51

7.19 Standard Setting on Zama Carburetors 54
7.19.1 C1Q-S30C, C1Q-S37A, C1Q-S41, C1Q-S42, C1Q-S34B, C1Q-S36B Fixed Jet Carburetors 54
7.19.2 C1Q-SK7, C3A-S39A Carburetors with Limiter Caps 55
7.20 Standard Setting on Tillotson Carburetors 59
7.20.1 Fixed Jet Carburetors: HS-275A, HS-279B 59
7.20.2 HL-366A, HS-280A, HS-281A, HT-12A Carburetors with Limiter Caps 60
7.21 Flow Chart 64
8. Special Servicing Tools and Aids 65
8.1 Special Servicing Tools 65
8.2 Servicing Aids 65

This Stihl Carburetor Service Repair Manual contains descriptions of repair and servicing procedures as well as functional diagrams of most carburetors used in STIHL gasoline power tools. While carrying out repair work you should make use of the latest illustrated parts list of the power tool concerned. It shows the installed positions and the assembly sequence of individual components and assemblies.
A fault on the carburetor may have several causes. Consult the troubleshooting chart.

View for free all the Stihl carburetor repair images online or download the full PDF for the Stihl Carburetor Service Workshop Manual, which you can view on any suitable device or print for workshop use. Available from the Stihl manuals page or from the site search button at the top of the page, Click to download.

Stihl Carburetors

The carburetor has to mix fuel and air in an optimum ratio for each phase of engine operation. It prepares the mixture for vaporization by breaking it down into fine droplets.
In the carburetor, fuel is atomized but not completely vaporized. The heat necessary to vaporize the fuel is taken from the components the fuel flows through, i.e. primarily the engine. Therefore, complete vaporization does not take place until the mixture reaches the combustion chamber. The absorption of vaporization heat by the fuel represents a form of cooling for the components that give off the heat. One talks about internal cooling.
The ideal fuel-air ratio (Lambda (l) = 1) is reached when the composition
of the mixture is 14.8 kg air to 1 kg fuel. Fuel burns cleanly at this mixture ratio. The mixture is combustible between Lambda 0.7 and 1.25. The mixture ratio deviates from the ideal value depending on the prevailing operating conditions (temperature, humidity, air pressure) and the operating phase (starting, idle, part load, full load). When the actual mixture ratio deviates from the ideal value, the mixture is said to be either rich or
lean. A lean mixture contains more air.

As there is a lack of fuel, the engine does not produce its full power. Furthermore, the engine overheats because insufficient heat is dissipated to vaporize the fuel. The lack of fresh gas containing oil results in inadequate lubrication and a risk of seizure. A rich mixture contains less air. Combustion is incomplete. Apart from other effects, unburned fuel is seen as smoke at the exhaust. A certain amount of oil is added to the fuel for lubrication of the bearings and piston.

Stihl Carburetor Service Repair Manual Diagrams

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