THERMO-Time Switch & Hot Start Relay

The thermo-time switch is affected by coolant or block temperature and starter current. Depending on engine temperature, the switch will take from 3-10 seconds to open. Injection through the cold start valve will then stop. Some models use a hot start pulse relay to improve hot starting. The relay will operate the cold start valve in short pulses after it would normally have been turned off by the thermo-time switch.