Briggs & Stratton 273521 manual Crankshafts And Camshafts, Remove Crankshaft and Camshaft, Inspect

CRANKSHAFTS AND CAMSHAFTS

Remove Crankshaft and Camshaft

1.Drain oil from engine and all fuel from fuel tank. Drain oil from gear reduction unit (if equipped) and remove from engine

(A, Figure 1).

2.Remove blower housing/rewind assembly and flywheel/fan assembly.

3.Remove burrs and clean crankshaft, then remove crankcase cover or sump. Set aside.

NOTE: If crankcase cover or sump sticks, tap lightly with soft hammer on alternate sides near dowel pins (B). It is not necessary to remove dowel pins.

6.Rotate crankshaft to place piston at Top Dead Center (TDC).

7.Remove connecting rod cap, then slide out crankshaft.

Inspect

Check Crankshaft

1.Inspect crankshaft for scoring on mag journal (A, Figure 3), crankpin journal (B), and PTO journal (C). Replace crankshaft is scoring is found or if crankshaft is bent. DO NOT attempt to straighten bent crankshafts.

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Figure 1

4.Carefully tip engine with PTO-end facing up.

5.Rotate crankshft until timing marks

(A, Figure 2) are aligned. With camshaft in this position, the valve tappets will remain clear of cam lobes. Lift out camshaft (B).

Figure 3

2.Using a dial caliper, measure the journal diameters and balancer eccentrics (if equipped). Compare results to values listed in Section 12 - Engine Specifications. If wear exceeds the reject dimensions, replace the crankshaft.

Check Camshaft

1.Check gear (A, Figure 4) for worn or damaged teeth. Check lobes (D) and journals (B, C) for scratching or scoring. Check compression release mechanism (A, Figure 5) for wear, burrs, or sticking. Replace camshaft if any of these conditions are found.

Figure 2

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