COOLING SYSTEM
adapter. The water reduces inner exhaust temperatures and cools the propeller hub.
- External water supply hoses
- Exhaust (plenum)
- Inner exhaust cooling hose
On 3.4 L models, propeller hub cooling water flows through an internal passage of the inner exhaust housing.
EMM and Vapor Separator Cooling
Cooling water is routed from the top of the cylinder block to the inlet fitting of the EMM water cavity. Cooling of the EMM helps to stabilize the temperatures of internal components.
IMPORTANT: Improper EMM cooling will activate service codes 25 and 29 and the Engine Monitor warning system. Refer to the EMM Service Code Chart at the back of this manual for specific service code information.
Cooling water from the EMM is routed to the water inlet fitting of the vapor separator water cavity. Cooling the vapor separator fuel chamber minimizes fuel vaporization.
Cooling water from the vapor separator is routed to the adapter/exhaust housing.
ENGINE TEMPERATURE CHECK
IMPORTANT: The engine temperatures listed below are based on an intake water temperature of 70° ± 10°F (21° ± 3°C).
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. Remember, running outboards at high speeds in test tanks may disrupt water flow to gearcase water intakes. Make sure the outboard has adequate water flow.
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.
Reduce speed to IDLE for five minutes. Check IDLE operating temperature.
Increase speed to 5000 RPM and check temperature.
Check temperature on both sides of powerhead.
If engine temperature is not within range, troubleshoot cooling system.
If engine temperature tests within range, but the SystemCheck gauge indicates a “WATER TEMP” warning, refer to WATER TEMP/ HOT Circuit Test on p. 146.
Software Method
Use Evinrude Diagnostics software to read temperature displays.
- Engine Monitor Screen
Typical temperature displays at IDLE speed should be 160°F ± 10°F (71°C ± 6°C)
Operating temperature must not exceed 194°F (90°C).
Pyrometer Method
Use a Temperature Gun, P/N 772018, or a digital pyrometer to measure the outboard’s operating temperature.
Measure temperature at the top of cylinder block, next to the thermostat housing and cylinder head. Check temperature on both sides of powerhead.
- Top of cylinder block (starboard side)
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 with a digital pyrometer, coat the probe location with Thermal Joint Compound, P/N 322170.
Idle Operating Temperature Troubleshooting (Below Range)
If engine IDLE temperature is below operating range 160°F ± 10°F (71°C ± 6°C), check thermostat and pressure relief valve operation.
Pressure Relief Valve
The pressure relief valve should be closed at IDLE speed. Water should not flow past the plunger and seal.
If IDLE temperature is below specific operating range, pinch off the water outlet hoses from pressure relief valve to cylinder heads.
- Outlet hoses
- Pliers
Use hose pinching pliers (acquired through local tool source) to prevent hose damage.
- Hose Pinching Pliers
Start the outboard and check IDLE operating temperature using Evinrude Diagnostics software program.
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 operating range with hoses pinched off, inspect thermostats and thermostat seals.
Thermostats
Remove thermostat cover(s) and inspect thermostat(s).
Check position of thermostat seal and how thermostat seals against cylinder head. Seal must be properly fitted to flange of thermostat.
- Seal, thermostat
Check thermostat for cracks, heat damage, or signs of corrosion. Check for proper operation. Thermostat opens at 143°F (62°C).
