FUEL SYSTEM/CARBURETION
4.9
MAIN SYSTEM
As throttle valve (1) is opened, engine speed rises,
and this increases negative pressure in the venturi.
Consequently the vacuum slide (2) moves upward.
Thefuelinfloatchamber(3)ismeteredbymainjet(4),
and the metered fuel enters needle jet (5), in which it
mixes with the air admitted through main air jet (6) to
form an emulsion. The emulsified fuel then passes
through the clearance between needle jet (5) and jet
needle (7), and is discharged into the venturi (A).
Mixture proportioning is accomplished in needle jet
(5); the clearance through which the emulsified fuel
must flow is determined ultimately by throttle position
and vacuum slide height.
1
A
5
4
3
6
7
2
PILOT SCREW
Thepilotsystemsuppliesfuelduring engineoperation
with the throttle valve closed or slightly opened. The
fuel/air mixture is metered by pilot screw and
dischargedintothemain bore throughthe pilot outlet.
CAUTION:
The pilotscrewiscalibr at edat thefactory to meetEPA / CARB
regul at ions for air qualit y standards and is sealed with a brass
plug t o pr event tamper i ng. Removal of the tamper proof plug
is not permi t ted. For ser vi ce purposes, cl eani ng of the pilot
cir cui tcan be done only by a cert i f ied repairshop to ensure air
quali t y standards are not exceeded.
Pilot Screw location
Brass Plug Installed
Brass Plug Removed
PartShark.com
877-999-5686
To Next Page
Loading...
Need help?
General
