10128050 Mariner OWNERS MANUAL

Inspecting and Adjusting Valve Clearance
The valve clearances should be inspected and adjusted when the engine is cold.Unit: mm (in.)
Adjusting valve clearance(1) Inspecting Valve Clearance
(a) Inspect each cylinder's valve clearance with the piston at the top-dead-center (TDC) position of its compression stroke. Follow the firing order, bringing the pistons to the TDC positions of their respective compression strokes by turning the crankshaft in the forward direction in increments of 180°.(2) Confirming Compression-Stroke TDC Position
(a) Bring piston No. 1 to the TDC position of its compression stroke. To do this, align the TDC mark on the crankshaft pulley with the mark on the gear case.(b) To confirm the compression-stroke TDC position, turn the crankshaft by approximately 20° in the forward and reverse directions and check for rocker-arm movement. When there is no rocker-arm movement, the piston is at the compression-stroke TDC position.(c) If rocker-arm movement occurs, the piston is at the TDC position of its intake or exhaust stroke. Give the crankshaft one more 180° turn to bring the piston to the TDC position of its compression stroke.(d) Start bringing the piston to the TDC position with cylinder No. 1 for inspection/adjustment of the valve clearance. Then, proceed to the other cylinder's pistons in accordance with the firing order. After cylinder No. 1, bring the piston in the next cylinder to its compression-stroke TDC position by turning the crankshaft in the forward direction (clockwise as seen from the timing gear case) by 180°. Finder orderCylinder Number: 1 - 3 - 4 - 2
Timing marks
Before starting the engine, place the timing gears in their original positions.
(3) Adjusting Valve Clearance
(a) Loosen the rocker arm nut, then adjust the clearance to the standard value using the adjusting screw and a thickness gauge (1).(b) Hold the adjusting screw in position while tightening the nut.
Adjusting valve clearance
When adjusting the valve clearances following disassembly and reassembly, turn the crankshaft two or three times then check again that the clearance are within specification.
Bleeding Air From Fuel System
Air should be bled first from the fuel filter and then from the injection pump, i.e., starting at the position closer to the fuel tank.(1) With the system with an electromagnetic-plunger-type fuel pump, turn the key to the ON position to force fuel to flow. Then, loosen the air vent screw (1), allow air in the filter to be expelled, and retighten the screw.(2) Loosen air vent screws (2) and (3) on the injection pump in that sequence to bleed air from the fuel pipe and injection pump.(3) When air-bleeding from screws (2) and (3) is complete, retighten each screw.(4) Air in the injection pipes and nozzles will be expelled automatically when the engine is cranked.
Bleeding air from fuel systemInspecting and Adjusting Injection Timing
(1) Preparation for Inspection
(a) Close the cock on the fuel filter.(b) Remove the No. 1 injection pipe.(c) Remove the No. 1 delivery valve holder, deliver valve, and spring. Then, refit only the delivery valve holder.
Removing delivery valve and spring(d) Connect the injection pipe on the pump side only to ensure that you can see when fuel stops flowing out.(e) Hold the speed control lever in low-speed position.(2) Inspection
(a) Open the cock on the fuel filter. If the system has an electromagnetic pump, turn the key to the ON position.
Fuel will flow out of the injection pipe. Make ready a container to catch it. If the system has an electromagnetic pump, caution is required since fuel will emerge with great force.
Fuel flow(b) Slowly turn the crankshaft clockwise. The injection timing is reached when fuel stops flowing out.
When fuel has stopped flowing out, turn the crankshaft slightly in the reverse direction such that fuel flows out. Then, slowly turn the crankshaft clockwise again to more accurately verify the point at which fuel stops flowing out.
End of fuel flow(c) If the IT mark on the crankshaft pulley and the mark on the gear case are aligned when fuel stops flowing out the injection timing is normal.
Timing marks(3) Adjustment
(a) If the injection timing is out of specification, make adjustments by increasing or decreasing the thickness of the injection pump's mounting shim. A change of 0.1 mm in the shim thickness yields a change of approximately 1° in the injection timing.
Injection timing adjusting shim(b) Increasing the shim thickness retards the injection timing, and decreasing the shim thickness advances it. Shims come in 9 different thicknesses from 0.2 mm (0.008 in.) to 1.0 mm (0.039 in.) at intervals of 0.1 mm (0.004 in.). The thickness is not indicated on the shim, so any shim should be measured with a vernier caliper before being used.
Before using any shim, apply sealant to both sides to prevent oil leakage.
(c) After making adjustments, check the injection timing is correct.(d) Close the cock on the fuel filter, then fit the delivery valve spring and injection pipe in their original positions.
Adjusting injection timingAdjusting Idle Speed
(1) Preparation for Adjustment
(a) Warm up the engine unit the coolant reaches a temperature of 60°C (140°F) or higher.(b) Make sure the valve clearances, injection timing, and injectors are normal.(2) Adjusting Low-Idle Speed
Loosen the locknut on the idling set bolt, turn the bolt to achieve the specified low-idle speed (1000 25min-1), then tighten the lock nut to hold the bolt in that position.(3) Adjusting No-Load Maximum Speed
Loosen the lock nut on the high-speed set bolt, turn the bolt to achieve the specified no-load maximum speed (2600 +30-10 min-1), then tighten the lock nut to hold the bolt in that pos