0435721 EVINRUDE THROTTLE BODY ASSY., 250

1. Remove the carbon from the top inside surface of the cylinder liners.2. Turn the crankshaft until two pistons are at bottom center.3. Remove bearing caps (1) from the two connecting rods. Put pieces of rubber hose or tape on the threads of the connecting rod bolts as protection for the crankshaft. 4. Push the pistons up until the piston rings are clear of the cylinder liner. Remove pistons (2). Keep each cap with the respective connecting rod.
Do not turn the crankshaft while any of the connecting rods are in the engine without the caps installed. Do not damage the cooling tubes when the pistons are removed.
5. Do Steps 1 through 4 for the remainder of the pistons.Install Pistons And Connecting Rods
1. Put clean engine oil on the piston rings, connecting rod bearings and cylinder liners.2. Put two pistons in position opposite of each other in the correct bore of the block. Install pistons (1) with tool (A).
Be sure that the pistons are installed with flat surfaces (2) of the connecting rods toward each other and the chamfered sides (4) toward the crankshaft.
For more detail about installation of connecting rod bearings and use of Plastigage [tool (B)], see Remove and Install Connecting Rod Bearings.3. Check the bearing clearances with tool (B).4. Put 2P2506 Thread Lubricant on bolts (5). Install caps (3) and nuts finger tight. Tighten each nut to a torque of 80 8 N m (60 6 lb.ft.). Put a mark across the nuts and bolts. Tighten each nut 120° more.5. Check the side clearance between two connecting rods on the same crankshaft journal. Clearance must be 0.076 to 0.838 (.003 to .033 in.) for new rods.6. Do Steps 1 through 5 for the remainder of the pistons.END BY:a. install oil pumpb. install cylinder headsDisassemble And Assemble Pistons And Connecting Rods
START BY:a. remove pistons and connecting rods 1. Remove bearings (2) from the connecting rod and connecting rod cap.2. Remove retainer ring (1). Remove piston pin (3) from the piston and connecting rod. 3. Use tool (A) to remove the piston rings (4) from the piston. 4. Heat the connecting rod to a temperature of 176° - 204°C (350° - 400°F). Put 5P8651 Spacer (12) in the base plate. Put connecting rod in position on the base plate of tooling (B).5. Put the connecting rod piston pin bearing end in the center of the port assembly of tooling (B). Install pin (8) in the center of the bore for the connecting rod bearings.6. Install 5P8653 Adapter (10). Put the hole in the adapter in alignment with the hole in the base plate of tooling (B).7. Install clamp bar (11) and clamp pin (7).8. Install new piston bearing (6) on adapter (10). The old bearing is pushed out by tooling (B) as the new bearing is installed.9. Put 5P8649 Adapter (9) in position as shown with the taper side down. The piston pin bearing joint must be in alignment with the hole in adapter (10) and the base plate of tooling (B).10. Put pusher (5) on adapter (9).11. Use tooling (B) to push the new piston pin bearing into the connecting rod until adapter (9) of tooling (B) makes full contact with the connecting rod surface.12. Remove the connecting rod and the old piston pin bearing from tooling (B).13. Check the piston pin bearing bore diameter after the bearing is installed. The correct dimension is 50.830 0.008 mm (2.0012 .0003 in.). 14. Clean the ring grooves in the piston before the rings are installed. The oil ring is to be installed over the spring with the oil ring and gap 180° from the oil ring spring joint. The two compression rings have marks "UP-1" and "UP-2". The rings must be installed with these marks toward the top of the piston with "UP-1" as the top ring. After installation of all three piston rings, put piston rings in position so gaps in rings are 120° apart.15. Use tool (A) to install the piston rings on the piston. Check the clearance between the ends of the piston rings. See the topic Pistons And Rings in the Specifications module. 16. Install bearings (2) in the connecting rod and connecting rod cap. Be sure the tabs in back of bearings are in the tab grooves of the connecting rod and connecting rod cap.17. Put piston (13) in position on the connecting rod. Put clean SAE 30 oil on piston pin (3), and install the piston pin. Install retainer rings (1). Make sure the retainer rings are in the grooves of the piston.END BY:a. install pistons and connecting rods