66853 Mercury SPRING, RETAINER PLATE TO STARTER SHEAVE

Illustration 1 g00454966
The arrow points to the front of engine.Bolt tightening sequence for three cylinder engines
Illustration 2 g00571930
Bolt tightening sequence for four cylinder engines
Remove the bolts in the cylinder head in the reverse sequence that is shown in Illustration 1 for three cylinder engines. Remove the bolts in the cylinder head in the reverse sequence that is shown in Illustration 2 for four cylinder engines. Remove the cylinder head from the engine.
Clean the cylinder head thoroughly. Make sure that the contact surface of the cylinder head and the contact surface of the cylinder block are clean, smooth and flat.
Inspect the bottom surface of the cylinder head for the following items: pitting, corrosion and cracks. Inspect the area around the valve seat inserts and the holes for the fuel injection nozzles.
Illustration 3 g00323904
Cylinder Head On The 8S-6691 Cylinder Head Stand Set (typical example)
Put the cylinder head on the 8S-6691 Cylinder Head Stand Set .
Illustration 4 g00454964
Positions for measuring the distortion of the face of the cylinder head and the cylinder block
Measure the cylinder head for flatness. Measure the flatness with a straight edge (1) and with a feeler gauge (2) .
Measure the cylinder block from point (A) to point (B) .
Measure the cylinder block from point (C) to point (D) .
Measure the cylinder block from point (A) to point (C) .
Measure the cylinder block from point (B) to point (D) .
Measure the cylinder block from point (A) to point (D) .
Measure the cylinder block from point (B) to point (C) .Refer to Specifications, "Cylinder Head" for the requirements of flatness.
Perform Step 6 in order to measure the face of the cylinder block for flatness. The top face of the cylinder block and the bottom face of the cylinder head have the same requirements for flatness.Valve Depth Check
Table 2
Required Tools    
Part Number    Part Name    Qty    
8T-0455     Liner Projection Tool Group     1    
Illustration 5 g00323908
8T-0455 Liner Projection Tool Group (1) 1P-2403 Dial indicator (2) 1P-2402 Gauge body (3) 1P-5507 Gauge block Use the 8T-0455 Liner Projection Tool Group to check the depths of the inlet valve and the exhaust valve below the face of the cylinder head.
Use gauge (3) in order to set dial indicator (1) to zero.
Illustration 6 g00323909
Valve Depth (1) 1P-2403 Dial indicator (2) 1P-2402 Gauge body
Measure the depth of the inlet valve and the exhaust valve below the cylinder head face before the valve springs are removed. Use gauge body (2) and dial indicator (1) in order to measure the depth.Refer to Specifications, "Cylinder Head Valves" for the minimum, the maximum, and the service wear limits for the valve depth below the cylinder head face. The minimum and the maximum limits are dimensions for a new engine.If the valve depth below the cylinder head face exceeds the specification for wear, replace one or more of the following components:
The valves
The valve inserts
The cylinder head
Check the valves for cracks and other damage. Check the valve stems for wear. Check that the valve springs are the correct length under the test force.Refer to Specifications, "Cylinder Head Valves" for the dimensions and tolerances of the valves and valve springs.