Outdoor Power Equipment, Small Engine, Lawn Mower Repairs, Troubleshooting and Safety
Disassembly, Cleaning and Repair of Kohler / Walbro WHG Adjustable 1 inch Carb
float type, side (horizontal) draft carburetor; adjustable main and idle fuel mixtures; adjustable idle speed.
Kohler carb part numbers: 45 053 71, 45 053 72, 45 053 73, 45 053 74, 45 053 75, 45 053 78, 45 053 79, 45 053 80, 45 053 81, 45 053 82, 45 053 83, 45 053 84, 45 053 90, 47 053 64, 47 053 65, 47 053 66, 47 053 67, 47 053 68, 47 053 69, 47 053 70, 47 053 71, 47 053 72, 47 053 74, 47 053 75, 47 053 79, 47 053 81, 47 053 82, 47 053 83, 47 053 84, 47 053 85, 47 053 86, 47 053 87, 47 053 88, 47 053 89, 47 053 90, 47 053 91, 47 053 92, 47 053 93, 47 053 94, 47 053 96, 47 053 97, 47 053 98, 47 053 99, 52 053 20, 52 053 21, 52 053 26, 52 053 27, 52 053 31, 52 053 32, 52 053 34, 52 053 36, 52 053 37, 52 053 38, 52 053 46, 52 053 47, 52 053 50, 52 053 51, 52 053 52, 52 053 54, 52 053 55, 52 053 56, 52 053 58, 52 053 59, 52 053 63, 52 053 66, 52 053 69, 77 053 01, 77 053 02, 77 053 03, 77 053 04, 77 053 05, 77 053 08, 77 053 09, 77 053 10, 77 053 11.
| Carb Initial Setting (turns out from lightly seated) | |||
|---|---|---|---|
| Engine Series | Walbro Fixed Jet-Low Idle (turns) | Walbro Adjustable Jet-Low Idle (turns) | Walbro Adjustable Jet-Main Fuel (turns) |
| K91 | N/A | 1-3/4 | 3/4 |
| K141 | N/A | N/A | N/A |
| K161 | N/A | 2-1/4 | 1-1/8 |
| K181 | 2-1/2 | 2-1/2 | 3/4 |
| K241 | 1-1/4 | 1-3/4 | 1-1/8 |
| K301 | 1-1/2 | 1-3/4 | 1-1/8 |
| K321 | 1-1/2 | 1-1/8 | 1-1/4 |
| K341 | 1 | 2-1/2 | 1-1/4 |
| KT17 | 1-1/4 | 1-1/4 | 1-1/4 |
| KT19 | 1-1/4 | 1-1/4 | 1 |
| M10 | 1-1/4 | 1-3/4 | 1-1/8 |
| M12 | 1-1/4 | 1-3/4 | 1-1/8 |
| M14 | 1-1/2 | 1-1/8 | 1-1/4 |
| M16 | 1 | 2 | 7/8 |
| M18 | 1-1/4 | 1-1/4 | 1-1/4 |
| M20 | 1-1/4 | 1-1/4 | 1 |
| MV16/18 | 1-1/4 | 1-1/4 | 1-1/4 |
| MV20 | 1-1/4 | 1-1/4 | 1 |
-
- #1. Kohler/Walbro WHG Carb
This carb is made by Walbro according to Kohler specifications (#1).
-
- #2. Fuel inlet
'Walbro' and 'WHG' are cast into the body of more recent carburetors (#2, pink).
-
- #3. Kohler part number
The Kohler part number is stamped on the carb mounting flange (#3). Older versions of this carb may have the 'WHG' series and date code stamped on the flange (#3, inset).
-
- #4. Float parallel to body
With the carb inverted the float should sit parallel to the carb body (#4). The metal float tab can be bent to adjust the level.
-
- #5. Float hinge rod
The float is held in place by the float hinge rod (#5). The inlet needle is attached to the float by a spring clip.
-
- #6. Inlet needle
When the float is removed, the inlet needle will come out with it (#6). Check the rubber tip of the inlet needle for wear, corrosion or damage.
-
- #7. Inlet needle seat
The conical rubber tip of the inlet needle is pushed upward by the float into the inlet seat (#7) as the fuel level in the bowl rises. The seat must be clean and smooth to make a good seal. It is not meant to be replaceable. If the seat is damaged, the carb should be replaced.
-
- #8. Main fuel pickup port
As fuel in the bowl enters the adjustable main fuel jet (#8, blue) it is metered by the needle screw (#8, green). The idle speed screw limits how far toward closed the throttle can travel thereby setting low idle speed (#8, yellow).
-
-
- #9. Fuel enters center pedestal
Fuel that has passed the adjustable main fuel jet enters into the center pedestal (#9, blue).
-
- #10. Idle fuel pickup
Fuel in the center pedestal can take either of two routes. The majority of the fuel goes into the larger passage which is the main emulsion tube (#10, yellow) or main nozzle. Air from the main air bleed mixes with the fuel as it travels up the tube to the nozzle where it enters the carb venturi. A small portion of the fuel goes up the smaller idle fuel transfer tube (#10, blue) for the low idle fuel circuit.
-
- #11. Idle fuel transfer tube
With the choke plate and shaft removed, the choke stop (#11, red) can be seen. Fuel from the emulsion tube is delivered into the venturi airstream at the main nozzle (#11, green). Fuel for the idle circuit flows up the idle fuel transfer tube (#11, blue).
-
- #12. Main and idle air bleeds
Just prior to the venturi, air enters the main air bleed (#12, green) and enters the the emulsion tube through a number of holes in the tube's side, mixing with the fuel. The fuel/air mixture continues up the tube to the main nozzle where it is discharged into the venturi airstream. The idle air bleed (#12, blue) is also located just prior to the venturi. Air enters the idle air bleed and mixes with fuel that has risen up through the idle fuel transfer tube. A large passage vents the carb bowl to the atmosphere (#12, pink).
-
- #13. Fuel mixture adjustment screws
A mixture of fuel from the idle fuel transfer tube and air from the idle air bleed flows through a passage (#13, red) in the carb body to a recess behind the welch plug (#13, yellow) and further on to the idle fuel mixture needle valve (#13, pink). The main fuel mixture needle is shown at #13, blue.
-
- #14. Adjusting needles
The main fuel mixture adjusting needle (#14, top) and the idle fuel mixture adjusting needle (#14, bottom).
-
- #15. Behind welch plug
In this photo the welch plug (#15, green) and idle mixture screw (#15, yellow) have been removed. A mixture of fuel from the idle fuel transfer tube and air from the idle air bleed flows through a passage (#15, pink) in the carb body to a recess behind the welch plug. One or more holes behind the welch plug (#15, red) lead into the airstream in the carb bore.
-
- #16. Idle fuel ports
View looking into the carb bore from the throttle end. One or more secondary fuel discharge, or 'off-idle' ports behind the welch plug lead into the carb bore (#16, pink). The primary idle fuel discharge port (#16, blue) is metered by the idle fuel mixture needle valve.
-
- #17. Choke plate
The choke plate is assembled as shown (#17) with the stamped numbers facing out and upright. The edges of the plate are chamfered. The choke closes in a counter-clockwise direction as viewed from the choke shaft lever. For convenience, if the choke plate is removed it should be marked.
-
- #18. Choke shaft, plate, detent ball and spring
There is a detent ball and spring (#18) to keep the choke in the open position.
-
- #19. Throttle plate
The edges of the throttle plate are chamfered. The throttle closes in counter-clockwise direction as viewed from the top (#19). For convenience, if the throttle plate is removed it should be marked.