Improvement of Carter Tyf - 1984 Carburetor Information

The 1984 Carter TYF carburetor is a refined version of the 1983 Carter TYF carburetor with the following improvements.

- The internal passageways for fuel and air in the carburetor have been modified in diameter to adapt to the requirements for the 1984 engine.

- Externally, the carburetor top has been changed at the opening for passageways leading to the frequency valve; the openings have been enlarged.

- An electric over vacuum solenoid to control cold choke operation via the choke diaphragm has been added. Power to operate this solenoid comes from the manifold heater power wire. Ground for the solenoid is at the back of the cylinder head. The operation of the solenoid is as follows:

With the ignition key in the crank position, power to the manifold heater is interrupted there by interrupting power going to the solenoid. The solenoid in this operating position channels vacuum directly from the intake manifold to the choke diaphragm causing the choke to open slightly allowing air into the carburetor for starting.

With the ignition key in the run position, power is supplied to the manifold heater (during cold engine condition) and in turn to the solenoid. This causes the solenoid to switch and channel vacuum from the intake manifold through a check valve, then to the choke diaphragm. The check valve is needed to trap vacuum to hold open the choke under partial acceleration to allow in adequate air to enable a smooth engine acceleration.

The trapped vacuum is allowed to bleed off when the ignition is switched to the OFF position causing power to the solenoid to be discontinued allowing the solenoid to switch and route the vacuum back to the intake manifold through the hose without the check valve.

- Vacuum retard for ignition timing will not be utilized, so the vacuum retard port of the carburetor will be plugged from the factory. Basic ignition timing is 2~ BTDC +/- 1~ at idle with the ignition advance vacuum hose disconnected and plugged.

- Basic idle speed is to be set at 920 RPM with a tolerance of +50 to -30 RPM (970 to 890 RPM).

- The oxygen sensor system for this carburetor system has been improved with the introduction of a barometric cell in the electronic control unit. This barometric cell enhances the fuel system's ability to compensate for varying altitude changes.

The duty cycle of the oxygen sensor system will vary from the initial setting according to the surrounding barometric pressure (altitude).

For the purpose of setting or checking of the duty cycle it is now necessary to know the surrounding barometric pressure (altitude). Once set correctly the system will be able to compensate for barometric pressure (altitude) changes that occur during normal driving.



1984 Rabbit