808308 Mercruiser BALL BEARING-COMMUTATOR END

Remove the cylinder head from the engine.
Remove the water temperature regulator housing.
Remove the valve springs and the valves.
Clean the cylinder head thoroughly. Make sure that the contact surfaces of the cylinder head and the cylinder block are clean, smooth and flat.
Inspect the bottom surface of the cylinder head for pitting, for corrosion, and for cracks. Inspect the area around the valve seat inserts and the holes for the fuel injection nozzles.
Illustration 1 g00323904
Cylinder head on the 8S-6691 Cylinder Head Repair Stand
Put the cylinder head on the 8S-6691 Cylinder Head Repair Stand (A).
Test the cylinder head for leaks at a pressure of 200 kPa (29 psi).
Illustration 2 g00295372
Measure the cylinder head for flatness.
(A) Side to side
(B) End to end
(C) Diagonal
Illustration 3 g00725548
Diagonal
(1) Straight edge
(2) Feeler gauge
Illustration 4 g00725605
Side To Side
(1) Straight edge
(2) Feeler gauge
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 one end to the opposite end (B).
Measure the cylinder block from one side to the opposite side (A).
Measure the cylinder block from one corner to the opposite corner (C).Refer to the Specifications Module, "Cylinder Head" topic for the maximum permissible amount of bow (curve of the cylinder head).Resurfacing the Cylinder Head
The cylinder head face can be resurfaced by removing metal from the face if the following conditions exist.
The cylinder head face is not flat within the specifications.
The cylinder head face is damaged by pitting, corrosion, or wear.
The thickness of the cylinder head must not be less than 102.48 mm (4.035 inch) after the cylinder head has been machined.If the cylinder head is resurfaced, the recesses for the valve seat inserts must be machined to the dimensions which are listed in the Specifications Module, "Cylinder Head Valves". The valve seat inserts must be ground on the side which is inserted into the cylinder head. Grinding this surface will ensure that no protrusion exists above the bottom face of the cylinder head. Grind the outer edge of the cylinder head side of the valve seat insert to a chamfer of 0.90 to 1.30 mm (0.035 to 0.051 inch) at 30 degrees to the vertical.Valve Tests
Timing of the Valves
Remove the valve mechanism cover and the water pump.
Set the piston of the No. 1 cylinder to the top center position on the compression stroke. Refer to the Systems Operation, Testing and Adjusting Module, "Finding Top Center Position for No. 1 Piston" topic.
Remove the front rocker arm and the inlet valve spring of the No. 1 cylinder. Note: In order to aid in the timing check of the inlet valves and exhaust valves, the valve lash is increased. By loosening the tension on the No. 1 inlet valve, a more accurate determination of the valve lash is allowed if the mark on the crankshaft pulley or the damper is within 2.5 degrees of the pointer indicator. Refer to Step 4.
Fasten a temporary pointer to the timing case cover. The tip of the temporary pointer should be near the outer edge of the crankshaft pulley or the damper. Make a temporary mark on the crankshaft pulley or the damper which aligns with the temporary pointer.
Remove the timing pin.
When the engine is viewed from the front, rotate the crankshaft in a clockwise direction. Rotate the crankshaft until the inlet valve of the rear cylinder is fully open.
Set the valve lash of the No. 1 inlet valve to 1.50 mm (0.059 inch).
When the engine is viewed from the front, rotate the crankshaft in a clockwise direction until the pushrod of the inlet valve for No. 1 cylinder begins to tighten. In this position, make sure that the mark on the crankshaft pulley or the damper is within 2.5 degrees of the temporary pointer indicator. Note: Use the following formula in order to calculate the measurement which is equal to 2.5 degrees on the pulley or damper.
Table 2
Formula For Calculating The Measurement on The Pulley or The Vibration Damper
(C X P) / 360 = M
C is the circumference of the pulley or the vibration damper.
P is equal to 2.5 degrees.
M is the measurement which is equal to 2.5 degrees on the pulley or the vibration damper.
If the timing is more than 2.5 degrees out of position, the timing gears are not in correct alignment. One tooth on the camshaft gear is equivalent to 23 mm (0.91 inch) at the circumference of a pulley of 203 mm (7.99 inch) diameter. If a large damper is installed, one tooth on the camshaft gear is equivalent to the following measurements:
35 mm (1.38 inch) at the circumference of a damper of 310 mm (12.20 inch) diameter
37 mm (1.46 inch) at the circumference of a damper of 327 mm (12.87 inch) diameter
When the engine is viewed from the front, rotate the crankshaft in a clockwise direction until the inlet valve of the rear cylinder is fully open. Refer to the Specifications Module, "Cylinder Head Valves" topic for the correct valve lash. Valve Depth Check
Table 3
Required Tools
Part Number Part Name Qty
8T-0455 Liner Projection Tool Group 1