807755 2 Mercruiser BELT, Serpentine

1. Turn the crankshaft until the timing mark on crankshaft gear (2) is in alignment with the timing mark on camshaft gear (1). To keep the engine timing correct during removal and installation of the crankshaft, put a mark on the teeth of the fuel injection pump drive gear and idler gear at location (A). Put a mark on the teeth of the idler gear and camshaft gear at location (B). The engine timing will be correct when the marks at locations (A) and (B) are in alignment and the timing marks on the crankshaft and camshaft gears are in alignment.2. Install a 3/4"-16 NF bolt in the gear end of the crankshaft. Install two 5/8"-18 NF bolts in the flywheel end of the crankshaft. Fasten a hoist to the crankshaft. 3. Remove main bearing caps (3).4. Remove the crankshaft from the cylinder block. The weight of the crankshaft is 145 lb. (65 kg). 5. Remove main bearings (4) from the block and from the caps. Remove the thrust bearings.Install Crankshaft
1. Clean the surfaces on the cyinder block for the main bearings. Install the upper halves of the main bearings in the block. Put clean engine oil on the bearings.2. Put the crankshaft in position in the cylinder block with a hoist. Make sure all of the timing marks are in alignment.3. Clean the Nos. 1 and 5 main bearing caps. Install new bearings in caps. Put clean engine oil on bearings. Temporarily install caps to hold crankshaft in place.
Make sure part number on cap is toward front of engine, and number on bottom of cap is the same as number on block when caps are installed.
4. Clean the Nos. 2, 3 and 4 main bearing caps. Install new bearings in the caps. Put clean engine oil on the bearings, bolts threads and surfaces of the washers that contact the caps.5. Check the bearing clearance with wire (A). Install the caps and tighten the bolts to a torque of 30 3 lb.ft. (40 4 N m). Put a mark on each bolt head and the bearing caps. Tighten the bolts 90° more. Remove the bearing caps and measure the thickness of the wire. The main bearing clearance (wire thickness) with new bearings must be .0030 to .0065 in. (0.076 to 0.165 mm). The maximum permissible clearance with used bearings is .010 in. (0.25 mm).6. Put the caps in position on the engine and install the washers and bolts. Tighten the bolts to a torque of 30 3 lb.ft. (40 4 N m). Put a mark on each bolt head and the bearing caps. Tighten the bolts 90° more.7. Remove the Nos. 1 and 5 main bearing caps. Follow the procedure in Steps 4 and 5 and check the main bearing clearance for the Nos. 1 and 5 main bearings.8. Follow the procedure in Step 6 and install the No. 1 main bearing cap. 9. Put clean engine oil on thrust bearings (1). Install the bearings with the grooves in the bearings against the crankshaft. Install the No. 5 main bearing cap. Tighten the bolts for the cap with the procedure in Step 6. 10. Check the crankshaft end play with tool group (B). The end play is controlled by the thrust bearings on the No. 5 main. The end play with new bearings must be .0025 to .0145 in. (0.064 to 0.368 mm). The maximum permissible end play with used bearings is .025 in. (0.64 mm). If a replacement has been made for any of the timing gears, it will be necessary to check the engine timing to make sure it is correct. See INSTALL FUEL INJECTION PUMP HOUSING AND GOVERNOR.end by:a) install pistonsb) install timing gear coverc) install flywheel housing