Edelbrock 8253, 8252, 8149, 8148, 8147 user manual

SPECIAL TUNING SUPPLEMENT FOR

MAIN JET-EQUIPPED CARBURETORS

Unlike most of the Edelbrock Performer
Series Carburetors, the carburetor you have
purchased is equipped with a main jet for
fuel metering above 2/3 throttle opening.

The following chart will help determine
which type of adjustment needs too be
performed.

Off-idle throttle response-Accelerator Pump
Idle to 1/3 throttle-Needle height
1/3 to 2/3 throttle-Needle size
2/3 to wide open-Main Jet

For adjustments other than main jet, please
refer to the main tuning manual.

MAIN JET ADJUSTMENTS

The main jet controls fuel flow from about
2/3 throttle to wide open. If you have a
problem in this area of throttle opening a
main jet change is in order. The main jet is
located in the bottom of the pick up tube
and can be accessed by removing the plug
in the bottom of the float bowl.

1. Turn fuel petcock to off position.

2. Remove aluminum plug from bottom of
float bowl using 11/16 (or 18mm) socket
or wrench. NOTE: It may be advantages to
loosen both clamps and rotate top of carb
towards the right side of the bike to gain
access to the plug and jet. Use a small cup
to drain fuel from bowl into while removing
plug. WARNING!! Gasoline and gasoline
fumes are extremely flammable. It is
strongly recommended when working with
gasoline, it be done in a well-ventilated
area away from any open flames or ignition
source.

3. Using a stubby flat-blade screwdriver
remove main jet from pick up tube. See
figure 1.

Figure 1

NOTE: If you need more fuel a larger # main jet
will be required. A smaller main jet will deliver
less fuel.

4. Install desired jet into pick up tube. Do not

over tighten jet as brass is soft and can easily
strip.

5. Replace bowl plug with O-ring. Do not over
tighten plug when reinstalling as it is hollow
and can easily crack or break. It is also

recommended a small amount of grease be
applied to the O-ring before re-installation.

MAIN JET SIZES AND PART NUMBERS
.062 #8140 .076 #8147
.064 #8141 .078 #8148
.066 #8142 .080 #8149
.068 #8143 .082 #8150
.070 #8144 .084 #8151
.072 #8145 .086 #8252
.074 #8146 .088 #8253

NOTE: Refer to Model Supplement for standard

main jet and alternate main jets supplied with
kit.