Outdoor Power Equipment, Small Engine, Lawn Mower Repairs, Troubleshooting and Safety
Disassembly, Cleaning and Repair of Medium Two-piece Flo-jet Carb (390323) on Briggs and Stratton Engine Model 195437 Type 0292
Briggs carb part numbers 293950, 390323, 394228, 394514
used on selected Models 146400, 146401, 146402, 146403, 146404, 146407, 146411, 146412, 146414, 146431, 146432, 146434, 146437, 146451, 146452, 146457, 146701, 146702, 146703, 146704, 146705, 146707, 147401, 147402, 147403, 147404, 147412, 147414, 147431, 147432, 147434, 147451, 147452, 147701, 147702, 170400, 170401, 170402, 170403, 170404, 170405, 170407, 170411, 170412, 170413, 170414, 170417, 170431, 170432, 170434, 170435, 170436, 170437, 170451, 170452, 170457, 170701, 170702, 170703, 170704, 170705, 170707, 171431, 171432, 171437, 171452, 171457, 190400, 190401, 190402, 190403, 190404, 190406, 190407, 190410, 190412, 190413, 190415, 190416, 190417, 190430, 190431, 190432, 190434, 190435, 190436, 190437, 190451, 190452, 190457, 190492, 190493, 190496, 190497, 191401, 191431, 191434, 191451, 191461, 193401, 193402, 193431, 193432, 193451, 194402, 194412, 194415, 194417, 195412, 195415, 195422, 195423, 195431, 195432, 195433, 195435, 195436, 195437, 195451, 195452, 195456, 195457, 200401, 200402, 200404, 200411, 200414, 200431, 200432, 200451, 200452, 200454, 231401, 231404, 231411, 231431, 231434, 231451, 231454, 231461, 233401, 233404, 233411, 233431, 233432, 233434, 233451, 233452, 233454, 233461
- Quick notes:
- The preset (preliminary adjustment) for both low (idle) and high (main) mixture needles is 1-1/2 turns out from lightly seated.
- The main jet (#3) and the emulsion tube (#4) must be removed before the carb upper body can be separated from the lower body (#11).
- When assembling the main jet onto the carb body, install and tighten the nut (#21) and then thread in the needle with its spring, washer and o-ring (#22).
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- #1. Briggs and Stratton Medium Two-piece Carburetor
Disassembly, Cleaning and Repair of the Medium Two-piece Flo-jet Carburetor shown here is mostly the same as the Large Two-piece Flo-jet Carburetor. The upper body has the fuel inlet fitting, inlet needle and seat, float, throttle and venturi. The lower body is made up of the float bowl, main jet and choke. The emulsion tube threads into the lower body and crosses diagonally up into the upper body.
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- #2. Idle mixture screw
The low idle needle (#2) meters fuel entering the carb throat while the throttle is near closed position (#25). The initial setting for the needle is 1-1/2 turns out (counter-clockwise) from lightly seated.
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- #3. Main needle assembly
The main jet needle assembly (#3) unscrews from the body. Any fuel in the carb bowl will drain out when this part is removed. The initial setting for the needle is 1-1/2 turns out (counter-clockwise) from lightly seated.
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- #4. Remove emulsion tube
Deeper inside the same hole that held the main needle is the emulsion tube (#4) that crosses diagonally up into the upper body (#20) just before the throttle plate.
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- #5. End view of emulsion tube
Be sure to use a screwdriver that snugly fits the slotted end of the tube (#5) since the tube is made of brass, a soft metal, and is easily stripped or damaged. If there is a build-up of gum, it may be necessary to soak the carb in cleaner prior to removal of the tube. When assembling, be sure to blow out any chips that may have been created.
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- #6. Emulsion tube
The emulsion tube (#6) has a number of holes along its length that must be clear in addition to the hole down the center (#5). This end of the center hole is the seat for the main fuel adjustment needle.
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- #7. Exploded view of main jet parts
#7 shows an exploded view of the parts that make up the main jet needle valve assembly and the emulsion tube.
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- #8. Worn main adjusting needle
This main jet needle (#8) shows significant wear, which will make it difficult to precisely adjust the main fuel flow.
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- #9. Top view of carb - three screws
After the emulsion tube has been removed, the upper body can be separated from the lower body by removing three screws (#9). It may be necessary to use a utility knife to loosen the gasket from the lower body.
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- #10. Separate upper and lower bodies
The upper body lifts straight out from the lower body. The gasket stays with the upper body (#10).
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- #11. Upper body lifts out
#11 shows a view of the two bodies and the float.
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- #12. Float should sit parallel to body
Invert the upper body and check to see that the float rests parallel to the body (#12) and that the needle moves up and down freely with the float.
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- #13. Upper body with float
The float is removed from the body by sliding out the hinge rod (#13). When you lift the float from the body, the float needle (inlet needle) will come with it and may slide off. Be careful not to lose it.
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- #14. Bend tang to adjust float
If the inlet needle, seat and float are in good condition, the float tang (#14) can be bent carefully so that the floats sits parallel to the upper body as in #12.
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- #15. Inlet needle with clip
The inlet needle is attached to the float by a clip (#15)
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- #16. Upper body with bowl gasket
#16 shows the upper body after removal of the float, with the gasket still in place.
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- #17. View of upper body
Carb upper body after removal of float and gasket (#17).
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- #18. Rubber inlet needle seat
A closer view of the inlet seat (#18). This carb has a replaceable rubber seat. Use a paperclip with a small hook on the end to pull it out, or blow through the fuel inlet fitting with compressed air. The seat has a groove on one side which must face inward. The needle mates with the chamfered hole on the side facing out.
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- #19. View down into carb bowl
A view of the float bowl of the lower body (#19).
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- #20. Installing emulsion tube
During reassembly, with the upper and lower bodies screwed together, be sure that the emulsion tube slips into the hole in the throat of the upper body (#20).
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- #21. Tighten bowl nut first
After installing the emulsion tube, when reassembling the main jet needle to the lower body, screw in and tighten only the nut first (#21). Then thread in the main adjustment needle with its spring, washer and o-ring (#22). This is so that you don't have the needle threaded too far into the nut when the nut is tightened, causing the needle to jam into the seat. Now, screw the needle in until just snug, then back it out 1-1/2 turns. This is the preliminary adjustment.
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- #22. Install main needle
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- #23. Manual choke lever
Manual choke lever assembly (#23).
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- #24. Choke plate and bowl vent tube
A view of the choke plate and the float bowl vent tube (#24).
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- #25. Throttle plate
A view of the throttle plate (shutter) and the idle fuel passage (#25).