Overhaul Inspections
BASIC MECHANICAL INSPECTIONSInspect the following and repair or replace parts if necessary.
1. Check the fuel paths (jets) and air paths (jets or orifices). If clogged, wash thoroughly with cleaning solvent or detergent and blow out with compressed air. Do not use metal wire or other metal pieces.
2. Check the diaphragms for damage and cracks.
3. Check that the needle valve operates with light pressure. If the valve is hard to slide or if it binds, replace it. If there is overflow, poor valve to seat contact is suspected. If the needle valve is responsible, replace it.
4. Check the fuel inlet filter (located above the needle valve) for clogging and damage.
5. Check the float operation. Check the float and lever for deformation or damage and replace if necessary.
6. Check operation of the throttle valve, choke valve and linkage. If they do not operate easily, wash well and apply engine oil sparingly to the shaft.
7. Check the float chamber cover and main body for damage or cracks.
COMPONENT INSPECTIONS
Inspect, and replace if defective, the following components before reassembly.
Slow Cut Solenoid Valve
Slow Cut Solenoid Power Check:
1. Apply battery voltage directly to the slow cut solenoid valve terminals.
2. Check that the valve operates with a click.
Slow Cut Solenoid Continuity Check:
3. Using a circuit tester, check that there is no continuity between the solenoid valve body and terminals.
Slow-cut Solenoid Valve Test:
4. Measure resistance between the terminals.
SCSV COIL RESISTANCE: 48-60 ohms at 68°F
FEEDBACK SOLENOID VALVE (FBSV)
Feedback Solenoid Power Check:
1. Apply battery voltage directly to the feedback solenoid valve terminals.
2. Check that the valve operates with a click.
Feedback Solenoid Mechanical Check:
3. Check that the jet is free from clogging.
Feedback Solenoid Continuity Check:
4. Using a circuit tester, check that there is no continuity between the solenoid valve body and the terminals.
Feedback Solenoid Valve Resistance Test:
5. Measure resistance between the terminals.
FBSV COIL RESISTANCE: 54-66 ohms at 68°F
BIMETAL ASSEMBLY
Bimetal Assembly Resistance Check:
Using a circuit tester, measure resistance between the terminal and body.
BIMETAL RESISTANCE: Approx. 6 ohms at 68°F
DASH POT
Dash Pot Check:
Check that the dash pot operates normally. Resistance must be felt when the dash pot is pulled. When the rod is released it must return quickly to the original position. If no resistance is felt when it is pulled, the diaphragm or the check valve is broken. If the rod returns slowly, the check valve is binding. In either case, replace the dash pot.
SECONDARY THROTTLE CHAMBER (DEPRESSION CHAMBER)
Secondary Throttle Diaphragm Check:
Check the secondary throttle chamber diaphragm for damage. First, push up the rod fully and closing off the nipple with a finger, release the rod. The diaphragm is intact if the rod does not return to the initial position with the nipple blocked off. if the rod returns, the diaphragm is broken. Replace the secondary throttle chamber.
THROTTLE POSITION SENSOR
Throttle Position Sensor Resistance Check:
1. Measure resistance between terminals 1 and 3 of the throttle position sensor.
TPS RESISTANCE: 3.5-6.5 k-ohms
2. Check the body for cracks and damage.