24 Series 4180 Powerhead
: Remove the gasket (1) and pump 
diaphragm (2).
If the gasket and diaphragm are 
stuck together, separate them 
carefully.
: Check the diaphragm and gasket 
and replace if necessary.
The diaphragm is the most delicate 
part of the carburetor. The 
diaphragm material is subjected to 
continuous alternating stresses and 
eventually shows signs of fatigue, 
i.e. the diaphragm distorts and 
swells and has to be replaced.
: Remove flange body (1) with idle 
speed screw.
: Remove the gasket (1) and pump 
diaphragm (2).
Reassemble in the reverse 
sequence.
: The pump diaphragm (1) and 
gasket (2) are held in position by 
the cast pegs on the flange body 
with idle speed screw (3).
: Gasket (1) and pump diaphragm 
(2) are held in place by the cast 
pegs on the end cover (5).
: Install the spring (4) and spring 
retainer (3) in the housing base 
(5). Fit the diaphragm (2) and 
gasket (1) and screw the 
assembly to the carburetor.
The spring retainer’s integrally cast 
guide points toward the spring (4).
– Fit the screws and tighten them 
down firmly.