VALVE CHECK ON 250 CG ENGINE INSTALL
VALVE CHECK ON 250 CG ENGINE PRO

The exact time the intake valves and exhaust valves open and close will effect the amount of power produced by the engine and at what RPM it is produced. Valve (Cam) timing can be quite complex or quite simple. Worse still, if the valves open at the wrong time they can be hit by the piston and bent. However, if these valves don't open and close at the right time the engine will not run. Thermostat opens at 143☏ (62☌).¶ To let the air/fuel mixture in to the engine we have intake valves. Inspect thermostat for cracks, heat damage, or signs of corrosion. Seal must be properly fitted to flange of thermostat. IMPORTANT: Check position of thermostat seal and how thermostat seals against cylinder head. Remove thermostat cover(s) and inspect thermostat(s).

If IDLE temperature is still below specific operating range with hoses pinched off, inspect thermostats and thermostat seals. If IDLE temperature increases to specific operating range, 160☏ ± 10☏ (71☌ ± 6☌), after pinching off hoses and eliminating water flow to the cylinder heads, pressure relief valve is leaking.

VALVE CHECK ON 250 CG ENGINE PRO

Start the outboard and check IDLE operating temperature using Evinrude Diagnostics software pro gram.

Use hose pinching pliers (acquired through local tool source) to prevent hose damage. If IDLE temperature is below specific operating range, pinch off the water outlet hoses from pres sure relief valve to cylinder heads. If IDLE temperature increases to specific operating range, pressure relief valve and thermostats are functioning properly. Water should not flow past the plunger and seal at IDLE speed. The pressure relief valve should be closed. Remember, cold running out boards prevent spark plugs from achieving proper operating temperatures. Check thermostats and pressure relief valve operation. If engine temperature is not within specified range, troubleshoot cooling system to determine problem. Idle Operating Temperature Troubleshooting (Below Range) 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 Typical temperatures observed at IDLE speed with pyrometer should be 143☏ ± 15☏ (62☌ ± 8☌)

Top of cylinder block (starboard side) 004339.

Check temperature on both sides of power head. Position infrared beam or pyrometer pickup at top of cylinder assembly, adjacent to the thermostat housing and cylinder head. Use a Temperature Gun, P/N 772018, or a digital pyrometer to accurately determine the outboard’s operating temperature. Typical temperature displays at IDLE speed should be 160☏ ± 10☏ (71☌ ± 6☌) Observe temperature displays for port and star board temperature sensors. Use the Evinrude Diagnostics Software program. Make sure the outboard has adequate water flow. Remember, running out boards at high speeds in test tanks may disrupt water flow to water intakes of the gear case. If engine temperature is not within this range, troubleshoot cooling system. At 5000 RPM, operating temperature must not exceed 160☏ (71☌). Reduce outboard speed and run engine at IDLE for five minutes.

Start outboard and run at 3000 RPM in FORWARD gear for at least five minutes.

VALVE CHECK ON 250 CG ENGINE INSTALL

Install correct test propeller and place outboard in a test tank or in the water. 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. IMPORTANT: For correct engine operating temperatures and RPM figures, the intake water temperature must be 70° ± 10☏ (21° ± 3☌).

Valve check on 250 cg engine