25096 Mercury NUT, LOWER MOUNT SCREW

Specifications
Table 1
    Inlet Valves     Exhaust Valves    
Valve Lash (Stopped Engine)     0.20 mm (0.008 inch)    
0.45 mm (0.018 inch)    
TC Compression Stroke     1 and 2     1 and 3    
TC Exhaust Stroke (1)     3 and 4     2 and 4    
Firing Order     1,3,4,2 (2)    
( 1 ) 360° from TC compression stroke
( 2 ) The No. 1 cylinder is at the front of the engine.
Table 2
TC Compression Stroke     Inlet Valves     Exhaust Valves    
Valve Lash    
0.20 mm (0.008 inch)    
0.45 mm (0.018 inch)    
Cylinders     1 and 2     1 and 3    
Table 3
TC Exhaust Stroke (3)     Inlet Valves     Exhaust Valve    
Valve Lash    
0.20 mm (0.008 inch)    
0.45 mm (0.018 inch)    
Cylinders     3 and 4     2 and 4    
( 3 ) Position for No. 1 cylinder
Table 4
Torque for Adjustment Locknut    
27 N m (20 lb ft)    Introduction
Refer to Specifications, "Engine Design" for the location of the cylinder valves.If the valve lash requires adjustment several times in a short period of time, excessive wear exists in a different part of the engine. Find the problem and make necessary repairs in order to prevent more damage to the engine.Not enough valve lash can be the cause of rapid wear of the camshaft and valve lifters. Not enough valve lash can indicate that the seats for the valves are worn.Valves become worn due to the following causes:
Fuel injection nozzles that operate incorrectly
Excessive dirt and oil are present on the filters for the inlet air.
Incorrect fuel settings on the fuel injection pump.
The load capacity of the engine is frequently exceeded.Too much valve lash can cause broken valve stems, springs, and spring retainers. Too much valve lash can be an indication of the following problems:
Worn camshaft and valve lifters
Worn rocker arms
Bent pushrods
Broken socket on the upper end of a pushrod
Loose adjustment screw for the valve lashIf the camshaft and valve lifters show rapid wear, look for fuel in the lubrication oil or dirty lubrication oil as a possible cause.Check Procedure
Valve Lash Check
An adjustment is NOT NECESSARY if the measurement of the valve lash is in the acceptable range. Check the valve lash while the engine is stopped. The temperature of the engine does not change the valve lash setting.
Table 5
   Inlet Valves    Exhaust Valves    
Valve Lash (Stopped Engine)    
0.20 mm (0.008 inch)    
0.45 mm (0.018 inch)    
TC Compression Stroke     1 and 2     1 and 3    
TC Exhaust Stroke (1)     3 and 4     2 and 4    
Firing Order     1,3,4,2 (2)    
( 1 ) 360° from TC compression stroke
( 2 ) The No. 1 cylinder is at the front of the engine.If the measurement is not within the acceptable clearance, adjustment is necessary.Adjustment Procedure
Valve Lash Adjustment
Note: The No. 1 cylinder is at the front of the engine.
Illustration 1 g00323903
Setting the valve lash (1) Adjustment screw (2) Feeler gauge