Cub Cadet MTD P71 Series - Manual (Page 31)

B ASIC T ROUBLESHOOTING
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6. Attach the leak down tester to an air supply of 90
psi.
7. Adjust the tester until the gauge’s needle is pointing
to the set position.
8. Connect the tester to the adapter.
NOTE: If the engine rotates it was not at top dead
center.
9. Check the reading on the gauge.
NOTE: If the reading is >15% pressure loss, investi-
gate for the cause of the leak by:
• Listen for air escaping through the carburetor
(intake valve leak)
• Listen for air escaping through the muffler
(exhaust valve leak)
• Listen for air escaping through the dipstick tube (blow by, head gasket leak)
NOTE: it is normal for a little leakage to be heard from the dipstick tube.
10. Disconnect the tester.
11. Rotate the engine to BDC.
12. Loosen the rockers to prevent them from opening the valves.
13. Re-attach the tester.
14. Compare the results.
NOTE: If the cylinder passes at TDC but fails at BDC, the bottom of the cylinder is scored. If it passes at BDC,
but not at TDC, the top of the cylinder is scored.
Figure 2.2
Leak down tester