Clean all carbon out of the insert

Figure 6-9. Engine base and oil pump removal.

TM-5-4930-228-14 Tank and Pump Unit Liquid Dispensing for Truck Mounting (Highland Industries Model 2000) FSN 4930-877-8678 Manual
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6-8 b . D i s a s s e m b l y . R e f e r t o f i g u r e 6 - 8 a nd disassemble the valves, valve seats, guides, and springs. 1 Lock (4) 2 Spring seat 3 Spring 4 Intake valve 5 Guide 6 Tappet (2) 7 Rotator 8 Spring 9 Exhaust valve 10 Cup (2) 11 Insert 12 Crankcase Figure 6-8. Valves, exploded view. c. Cleaning, Inspection, and Repair. (1) Clean the valves with a wire brush to remove all carbon deposits. Clean valve seats, ports, and guides in cylinder block; clean top of cylinder block. Wash springs with cleaning solvent and dry thoroughly. ( 2 ) I n s p e c t v a l v e s f o r b u r n e d , p i t t e d , or cracked faces: replace a burned, cracked, or deeply pitted valve. (3) Inspect valves springs for cracks or pitting. Replace cracked or pitted springs. (4) Inspect valve seat insert for looseness and pitting. Replace a defective valve seat insert in the following manner: (a) Use a puller to remove the insert from the exhaust valve opening. ( b ) C l e a n a l l c a r b o n o u t o f t h e i n s e rt counterbore in the cylinder block and clean the valve stem guide bore. (c) Finish the counter bore in the cylinder block to provide the correct bore-to-insert in- terference. Chill the insert with dry ice and, using a pilot driver, tap the insert into place with light blows. Peen the insert to anchor in place. (d) Reface the insert, if necessary, to make its seat concentric with the valve. Check con- centricity with a dial indicator. (c) Lap valve in seat to form a gas-tight seat. d. Regrinding Valves. (1) Using a valve seat grinding tool, grind the seats at a 45° angle and then grind the valve faces at a 45° angle with a valve refacer grinder. (2) Valves must be lapped with a suitable lapping compound or they will leak within the first few hours of operation because of improper seating. (3) Clean valve seat and faces with cleaning solvent and dry thoroughly. (4) After lapping the valves, remove them from the block and wash the valves and block with cleaning solvent. e . R e a s s e m b l y . R e f e r t o f i g u r e 6 - 8 a nd reassemble valves. f. Installation. (1) Install valve inspection cover (para 6-8). (2) Install cylinder head (para 6-7). (3) Install carburetor (para 4-25). (4) Install engine (para 6-5). 6-10. Engine Base and Oil Pump a. Removal. (1) Remove the engine (para 6-5). (2) Refer to figure 6-9 and remove the engine base and oil pump. b . D i s a s s e m b l y . R e f e r t o f i g u r e 6 - 1 0 a nd disassemble the engine base and oil pump. c. Cleaning, Inspection, and Repair. (1) Clean all parts with cleaning solvent and dry thoroughly.

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