Engine Maintenance

Hours on the Engine

  Checks and Work 10 Every 12.5 25 50 75 100 125 150 175 200 225 250 275 300
1 Retorque Heads (air-cooled engines)(1) x - - - - - - - - - - - - - -
2 Retorque Exhaust Manifold Bolts(1) x - - - - - - - - - - - - - -
3 Check rewind starter rope - - x - - - - - - - - - - - -
4 Check electric starter gear - - - - x - x - x - x - x - -
5 Inspect spark plugs - - x - - - - - - - - - - - -
6 Replace spark plugs - - - x x x x x x x x x x x x
7 Check and clean inside of spark plug caps - - x - - - - - - - - - - - -
8 Check ignition timing (points ignition) - x(2) - - - x - - - - - x - - -
9 Check point gap - x(2) - - - x - - - - - x - - -
10 Check ignition damping box - - - - - x - - x - - x - - -
11 Replace points and condensers - - - - - - - - x - - - - - -
12 Check fan belt - x - x x x x x x x x x x x -
13 Lubricate ball joints - - - x x x x x x x x x x x -
14 Replace exhaust springs - - - - - x - - x - - x - - -
15 Oil control cables - - - x x x x x x x x x x x -
16 Check propeller balance and tracking (3) - - - x x x x x x x x x x x -
17 Inspect propeller mounting bolts (4) - - - - - - - - - - - - - - -
18 Clean and oil air filter - - - x x x x x x x x x x x -
19 Check fuel filter - - - x x x - x x x - x x x -
20 Replace fuel filter - - - - - - x - - - x - - - -
21 Check carburetor(s) and re-adjust idle speed, cable tension etc. x - - x - x - x - x - x - x -
22 Clean carburetor(s) and check for wear - - - - x - x - x - x - x - -
23 Replace jet needle and needle jet - - - - - - - - x - - - - - -
24 Clean and check fuel pump - - - - - x - - x - - x - - -
25 Check gearbox oil level - - - x x x - x x x - x x x -
26 Replace gearbox oil - x - - - - x - - - x - - - -
27 Check and adjust gearbox, preload for type A and B - - - - - - x - - - x - - - -
28 Check gearbox back plate screws for type A - - - - - - x - - - x - - - -
29 Replace rotary valve oil - - - - - - x - - - x - - - -
30 Inspect cylinder head and piston crown (5) - - - - x - x - x - x - x - -
31 Inspect piston ring groves (6) - - - - x - x - x - x - x - -
32 Check piston diameter (8) - - - - x(7) - x(7) - x - x (7) - x(7) - -
33 Piston ring: check gap (8) - - - - x(7) - x(7) - x - x(7) - x(7) - -
34 Piston ring: check axial play (rectang. ring)(8) - - - - x(7) - x(7) - x - x(7) - x(7) - -
35 Check cylinder diameter - - - - x(7) - x(7) - x - x(7) - x(7) - -
36 Cylinder: check roundness (8) - - - - x(7) - x(7) - x - x(7) - x(7) - -
37 Replace cylinder head, cylinder base, intake, and exhaust gaskets (9) - - - - x - x - x - x - x - -
38 Inspect piston pin and bearing - - - - - - - - x - - - - - -
39 Inspect crankshaft and replace outer seals  - - - - - - - - x - - - - - -
40 General overhaul of the engine - - - - - - - - - - - - - - x

(1) and after every replacement of gaskets
(2) and after every replacement of contact breakers
(3) also after any damage
(4) according to instructions of manufacturer
(5) if carbon is more than .020" thick, decarbonize
(6) if piston rings stick, clean and replace if necissary
(7) if used in very dusty atmosphere
(8) wear limit see SI 5 UL 91
(9) if cylinders get dismantled
(10) overhaul every 300 hours or 5 years which ever comes first. 

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