881879A20 Mercury SENSOR ASSEMBLY, Pressure, Water Pressure

Start By:a. remove oil pumpb. remove oil pan plate 1. Turn the crankshaft until two pistons are at the bottom center. Remove connecting rod caps (2) from the two connecting rods. Remove the lower half of the rod bearing from the rod bearing cap.
The connecting rod bolts are loose on the connecting rods and can fall out when the nuts are removed.
2. Push connecting rods (1) away from the crankshaft. Remove the upper half of the rod bearing from the connecting rod. Install the connecting rod bearings dry when the clearance checks are made. Put clean engine oil on the connecting rod bearings for final assembly.
Be sure the tabs in the back of the connecting rod bearings are in the tab grooves of the connecting rod and cap.
3. Install the upper half of the rod bearing in the connecting rod, and put the connecting rod in position on the crankshaft.4. Install the lower half of the rod bearing in the connecting rod cap. The serviceman must be very careful to use Plastigage, tool (A) correctly. The following points must be remembered:...Make sure that the backs of the bearings and the bores are clean and dry....Make sure that the bearing locking tabs are properly seated in their slots....The crankshaft must be free of oil where the Plastigage touches it....Put a piece of Plastigage on the crown of the bearing half that is in the cap. Do not allow the Plastigage to extend over the edge of the bearing....Install the bearing cap using the correct torque-turn specifications. Do not use an impact wrench. Be careful not to dislodge the bearing when the cap is installed....Do not turn the crankshaft with the Plastigage installed....Carefully remove the cap but do not remove the Plastigage. Measure the width of the Plastigage while it is in the bearing cap or on the crankshaft journal. Do this by using the correct scale on the package. Record the measurements....Remove the Plastigage before reinstalling the cap.When using Plastigage, the readings can sometimes be unclear. For example, all parts of the Plastigage are not the same width. Measure the major widths to make sure that they are within the specification range. Also, experience has shown that when checking clearances tighter than 0.10 mm (.004") the readings may be low by 0.013 to 0.025 mm (.0005 to .0010"). Out-of-round journals can give faulty readings. Also, journal taper may be indicated when one end of the Plastigage is wider that the other.For complete details concerning measuring bearing clearances, see Engine Bearings And Crankshafts, Form No. SEBD0531.5. Use Plastigage (A) to check the connecting rod bearing clearance.6. Put Plastigage (A) on the connecting rod bearing.7. Put clean 2P2506 Thread Lubricant on the threads of the rod bolts and seat surfaces of the nuts.
When connecting rod caps are installed, make sure the number on the side of the cap is next to and respective with the number on the side of the connecting rod.
8. Install connecting rod cap (2). Install the nuts. Tighten the nuts to a torque of 40 4 N m (30 3 lb ft). Put a mark on each nut and the end of each bolt. Tighten the nuts 90° more. Remove the connecting rod caps. Remove Plastigage (A), and measure the thickness of the Plastigage. The connecting rod clearance must be 0.076 to 0.168 mm (.0030 to .0066 in) for new bearings. The maximum clearance with used bearings is 0.25 mm (.010 in).9. Install the connecting rod caps, and tighten the nuts as in Step 8.10. Do Steps 1 through 9 for the remainder of the connecting rod bearings.End By:a. install oil pan plateb. install oil pump.