20 Series 4180 Powerhead
Troubleshooting, b 4.4
In the event of trouble with the 
carburetor, first check the fuel 
supply, b 6.6, and tank vent, 
b 6.5
The carburetor can be tested for 
leaks with the carburetor and 
crankcase tester 1106 850 2905.
– Remove the air filter, b 6.1
– Open the tank filler cap to relieve 
pressure.
– Close the tank filler cap.
: Pull fuel hose (1) off carburetor’s 
elbow connector.
: Push the fuel hose (1) 
1110 141 8600 onto 
the nipple (2) 0000 855 9200.
: Push the fuel hose (1) with nipple 
(2) onto the carburetor elbow 
connector.
– Push the pressure hose of tester 
1106 850 2905 onto the nipple.
: Close the vent screw (1) on the 
rubber bulb.
: Pump air into the carburetor with 
the rubber bulb (2) until the 
pressure gauge (3) indicates a 
pressure of 0.8 bar.
If this pressure remains constant, 
the carburetor is airtight.
– Disconnect pressure hose and 
carburetor tester.
– Refit the fuel hoses.
Reassemble all other parts in the 
reverse sequence.
However, if it drops, there are two 
possible causes:
1. The inlet needle is not sealing 
(foreign matter in valve seat, sealing 
cone of inlet needle is damaged or 
inlet control lever is sticking).
2. The metering diaphragm is 
damaged.
In either case the carburetor must 
be removed and serviced, b 6.2.
– After completing test, open the 
vent screw on the carburetor and 
crankcase tester and disconnect 
the test hose from the carburetor.
6.2 Carburetor
6.2.1 Leakage test