Compatible — Tappet Adjustment

For these models: 3054 Marine Engine, 3054 Marine Engine (Turbocharged), 3056 Marine Engine.

Procedure

1. Remove ignition key to prevent accidental star-
2. Remove all parts necessary to gain access to
3. Remove spark plugs to ease the task of turning
4. Use the engine flywheel to turn the engine over
5. The correct feeler gauge for the valve adjustment
6. To correct the valve clearance, use a 7/16-inch
7. To adjust valves on the right hand cylinder, turn
8. Replace all parts removed in Step 2. Tighten all
9. Turn the flywheel mounting screw outward about
10. Install a puller bar on the flywheel as shown in
11. Turn the puller bar bolts in, alternately, until the
12. Unscrew the puller from the flywheel, remove the
13. FLYWHEEL
14. Drain oil.
15. Remove the cylinder head and oil base pan from
16. Remove the ridge from the top of each cylinder
17. Turn the crankshaft until the piston is at the
18. Inspect the pistons for fractures at the ring
19. Replace pistons showing signs of scuffing,
20. Replace connecting rod bolts and nuts with

Source: manual:965-0161 Onan B48M Operator's and Service Manual (3-1985).pdf. Figures and steps are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.