ENGINE TEMPERATURE CHECK
IMPORTANT: For correct engine operating temperatures and RPM figures, the intake water temperature must be 70° ± 10°F (21° ± 3°C).
When servicing the propeller, always shift the outboard to NEUTRAL, turn the key switch OFF, and twist and remove all spark plug leads so the engine cannot be started accidentally.
Install correct test propeller and place outboard in a test tank or in the water. Start outboard and run at 3000 RPM in FORWARD gear for at least five minutes. Reduce outboard speed and run engine at IDLE for five minutes. Check IDLE operating temperature. Increase outboard speed to 5000 RPM. At 5000 RPM, operating temperature must not exceed 160°F (71°C). Check temperature on both sides of power head. If engine temperature is not within this range, troubleshoot cooling system. Remember, running out boards at high speeds in test tanks may disrupt water flow to water intakes of the gear case. Make sure the outboard has adequate water flow.
Software Method
Use the Evinrude Diagnostics Software program. Observe temperature displays for port and star board temperature sensors.
Engine Monitor Screen 005141
Typical temperature displays at IDLE speed should be 160°F ± 10°F (71°C ± 6°C)
Pyrometer Method
Use a Temperature Gun, P/N 772018, or a digital pyrometer to accurately determine the outboard’s operating temperature. Position infrared beam or pyrometer pickup at top of cylinder assembly, adjacent to the thermostat housing and cylinder head. Check temperature on both sides of power head.
- Top of cylinder block (starboard side) 004339
Typical temperatures observed at IDLE speed with pyrometer should be 143°F ± 15°F (62°C ± 8°C)
IMPORTANT: If you get low or inaccurate readings during these tests, coat the probe location of the digital pyrometer with a liberal amount of Thermal Joint Compound, P/N 322170
Idle Operating Temperature Troubleshooting (Below Range)
If engine temperature is not within specified range, troubleshoot cooling system to determine problem. Check thermostats and pressure relief valve operation. Remember, cold running out boards prevent spark plugs from achieving proper operating temperatures.
Pressure Relief Valve
Verify engine temperature at IDLE. The pressure relief valve should be closed. Water should not flow past the plunger and seal at IDLE speed.
Pressure Relief Valve DRC8113
If IDLE temperature increases to specific operating range, pressure relief valve and thermostats are functioning properly. If IDLE temperature is below specific operating range, pinch off the water outlet hoses from pres sure relief valve to cylinder heads.
- Outlet hoses DSC00827
- Pliers
Use hose pinching pliers (acquired through local tool source) to prevent hose damage.
Hose Pinching Pliers DSC00830
Start the outboard and check IDLE operating temperature using Evinrude Diagnostics software pro gram.
If IDLE temperature increases to specific operating range, 160°F ± 10°F (71°C ± 6°C), after pinching off hoses and eliminating water flow to the cylinder heads, pressure relief valve is leaking. Replace pressure relief valve. If IDLE temperature is still below specific operating range with hoses pinched off, inspect thermostats and thermostat seals.
Thermostats
Remove thermostat cover(s) and inspect thermostat(s).
IMPORTANT: Check position of thermostat seal and how thermostat seals against cylinder head. Seal must be properly fitted to flange of thermostat.
- Seal, thermostat DSC02335
Inspect thermostat for cracks, heat damage, or signs of corrosion. Check thermostat for proper operation. Thermostat opens at 143°F (62°C).
