Mercury YS4Z-6505-AA Valve - Exhaust

You can Select Your Vehicle to check if YS4Z-6505-AA fits your vehicle.

No, the desired clearances for intake and exhaust valves are different.

10. If the valve clearance was too small, install a thinner shim; if too large, install a thicker shim. The required thickness of the new shim can be calculated as follows: Sample calculation for clearance too small: Desired clearance (A) equals 0.15 mm Measured clearance (B) equals 0.09 mm Shim thickness found (C) equals 2.55 mm Thickness required (D) equals C + 8 - A equals 2.49 mm Sample calculation for clearance too large: Desired clearance (A) equals 0.30 mm Measured clearance (B) equals 0.36 mm Shim thickness found (C) equals 2.19 mm Thickness required (D) equals C + 8 - A equals 2.25 mm.

1. Examine the head of each valve for pitting, burning, cracks, and general wear, and check the valve stem for scoring and wear ridges. 2. Rotate the valve and check for any obvious indication that it is bent. Look for pits and excessive wear on the tip of each valve stem. Replace any valve that shows signs of wear or damage. 3. If the valve appears satisfactory, measure the valve stem diameter at several points using a micrometer. Any significant difference in the readings indicates wear of the valve stem, and the valve(s) must be replaced if conditions are apparent. 4. If the valves are in satisfactory condition, they should be ground (lapped) into their respective seats to ensure a smooth gas-tight seal.