Inlet Needle; Pump Diaphragm - Stihl 4180 Series Service Manual

Installing
5
6
2
Fit a new gasket (6) and metering diaphragm (5) – the
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small hole (arrow) in the gasket and metering
diaphragm (5) must be on the same side as the
adjusting screws.
Fit bulb (3) in the annular groove (arrow) in the flange
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(4).
Fit the end cover (2).
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Line up the flange (4) so that both fuel connectors
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(arrows) are opposite the adjusting screws.
Fit two screws (1) to hold the gasket (6) and metering
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diaphragm (5) in place.
Fit the other screws (1).
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Tighten down the screws (1) firmly in a crosswise
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pattern.
Install the carburetor, @ 10.2
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Check operation:
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11.6

Inlet Needle

Removing
Remove the metering diaphragm (5).
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11
10
1
Use T8 screwdriver 5910 890 2310 to remove the
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screw (11).
Pull the inlet control lever (7) with spindle (8) out of
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the groove in the inlet needle (10) – the spring (9)
under the inlet control lever (7) may pop out.
Take out the spring (9), inspect it and renew if
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necessary.
Pull out the inlet needle (10), inspect it and renew if
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necessary.
28
3
4
1
8 7
10
If there is an annular indentation (arrow) on the sealing
cone of the inlet needle (10), fit a new inlet needle.
Installing
Fit the inlet needle (10), pointed end first, in the
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carburetor.
Fit the spring (9).
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Position the inlet control lever (7) with spindle (8) on
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the spring (9) first, then slide the inlet control lever's
clevis into the annular groove in the inlet needle (10).
The spring (9) must locate in the inlet control lever's (7)
recess.
Press the inlet control lever (7) down and secure it
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with the screw (11).
Check that the inlet control lever (7) moves freely.
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Install the metering diaphragm (5).
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11.7

Pump Diaphragm

Removing
Remove the carburetor, @ 10.2
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Take out the screws (33).
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Remove the end cover (32) – the spring (34) and
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washer (35) may drop out.
Carefully remove the gasket (31) and pump
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diaphragm (30) from the pegs on the end cover (32).
Carefully separate the pump diaphragm (30) and
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gasket (31).
Examine the pump diaphragm (30) for damage and
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wear, replace if necessary. If the pump diaphragm
(30) is distorted, fit a new one.
Clean the strainer (29) – if necessary, use a scriber to
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remove the strainer from the carburetor body.
Replace the gasket (31).
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Installing
35 32
34
30
Push the strainer (29) into its seat in the carburetor
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body. Raised side of strainer (29) faces inwards.
Fit the spring (35) and washer (35) on the end cover
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(32).
Place the gasket (31) on the end cover (32) so that
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the pegs (arrows) hold it in position.
Place the pump diaphragm (30) on the gasket (31)
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and over the pegs (arrows).
31
32
33
Series 4180 Powerhead