Prelude L4-1958cc SOHC (1988)
Fig. 7 Fast idle adjusting screw location.
1.
Start engine and warm to normal operating temperature, then turn engine off.
2.
Disconnect both coolant hoses from thermowax valve and cap end of hoses.
3.
Apply cold water through thermowax valve to cool down wax.
4.
Connect tachometer and check idle speed.
5.
Adjust idle speed, if necessary, by turning fast idle adjusting screw, Fig. 7.