809145 Mercruiser SET SCREW

To prevent damage to the intake and exhaust valves an adjustment must be made to the valve clearance setting. Loosen the nuts on each rocker arm, and move the adjustment screw on each rocker arm away from the bridge as far as possible.
1. Put the engine in position on tooling (A). Use tooling (A) to turn the engine so that the crankshaft is up as shown.2. Remove the breather tube and the air cleaner housing and support from the left side of the engine (as seen from the flywheel end of the engine).3. Turn the engine over on its side. Make sure the blocks that are used as support for the top of the engine are against the cylinder head only and not against the exhaust manifold or valve cover bases. 4. Loosen the nuts that hold each connecting rod bearing cap (1) in position. Turn the crankshaft if necessary to loosen all the nuts. Make sure the nuts are still tight enough to hold the bearing caps in place when the crankshaft is turned. 5. Turn the crankshaft so that "V" mark (2) on the crankshaft gear is in alignment with "V" mark (3) on the idler gear.6. Remove the bearing caps that hold the connecting rods in position against the crankshaft. 7. Remove bearings (4) from each bearing cap. Make sure that each bearing is kept with the bearing cap it is removed from for correct installation purposes. 8. Remove all crankshaft main bearing caps (5).9. Push the pistons as far away as possible from the crankshaft. 10. Remove bearing (6) from each crankshaft main bearing cap. Make sure that each bearing is kept with the crankshaft main bearing cap it is removed from for correct installation purposes. 11. Remove two thrust plates (7) from the center main bearings. 12. Fasten tooling (B) and a hoist to the crankshaft as shown.13. Use tooling (B) and a hoist to remove crankshaft (8) from the cylinder block. The weight of the crankshaft for a 3408 Engine is approximately 131 kg (290 lb.). Lift the crankshaft slowly so the main bearing upper halves stay in the cylinder block. 14. Use tool (C) to remove gear (9) from the crankshaft. Use tooling (D) to remove the dowel that is under the gear if a replacement of the dowel is necessary. 15. Use tooling (E) to remove pin (10) from the crankshaft if a replacement of the pin is necessary. 16. Put identification on main bearing upper halves (11) and connecting rod bearing upper halves (12) as to their location in the cylinder block and connecting rods. Remove bearings (11) and (12).Install Crankshaft
Do not put oil on the bearings until the bearing clearance has been checkd.1. Install bearings (1) in the connecting rods they were removed from. Make sure the hole in each bearing is in alignment with the notch in each connecting rod.2. Install bearings (2) in the cylinder block. Make sure the tab in each bearing is in alignment with the notch in the cylinder block. For further information on bearing clearances, see Remove And Install Crankshaft Main Bearing. 3. Install pin (3) in the end of the crankshaft. Install the pin so that it extends a maximum of 6.4 mm (.252 in.) above the surface. 4. Install the dowel in the crankshaft that puts gear (4) in the correct position. Install the dowel so that it extends 4.1 0.5 mm (.161 .020 in.) above the surface of the crankshaft.5. Heat gear (4) to a maximum temperature of 233°C (451°F). Gear (4) must be installed on the crankshaft with the "V" timing mark toward the outside.6. Install gear (4) on the crankshaft. Make sure the notch in the gear is in alignment with the dowel on the crankshaft. The dimension from the rear face of the gear to the front face of the crankshaft must be 45.54 0.25 mm (1.793 .010 in.). 7. Fasten tooling (A) and a hoist to the crankshaft (5) as shown. Install the crankshaft in the engine. The weight of a crankshaft for a 3408 Engine is approximately 131 kg (290 lb.). 8. Make sure that "V" mark (6) on the crankshaft is in alignment with "V" mark (7) on the idler gear. The side of each thrust plate (8) with the words "BLOCK SIDE" must be installed with this side toward the cylinder block.9. Put clean oil on thrust plates (8). Install thrust plates (8) next to the center main bearings. Do not put oil on bearings (9) until the bearing clearances have been checked.10. Put bearings (9) in their original position in crankshaft main bearing caps (10).11. Check the crankshaft main bearing clearance with Plastigage as follows: For service tips on the use of Plastigage, see the topic Install Crankshaft Main Bearings.a. Put a piece of Plastigage between the crankshaft bearing journal surface and bearing (9).b. Install the crankshaft main bearing caps (10) with the arrow on each cap toward the front of cylinder block. Each crankshaft main bearing cap has a number on the bottom surface and must be installed in the same position as the correct number on the left side of the cylinder block.c. Put 2P2506 Thread Lubricant on the threads of the cap bolts. Install the cap bolts finger tight.d. Tighten the bolts on the tab end of the caps first to a torque of 258 14 N m (190 10 lb.ft.).e. Tighten the bolts on the other end of the caps to a torque of 258 14 N m (190 10 lb.ft.).
Do not use an impact wrench to tighten the bolts the additional 120°.
f. Put a mark across the bolt head and cap. Tighten the bolts opposite the tab end of the cap 120° more. Tighten the bolts on the tab end of the cap 120° more.12. Remove the crankshaft main bearing caps, and measure the Plastigage. The clearance for new bearings must be 0.91 to 0.186 mm (.0036 to