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How to take tappet clearance and adjust it ?

  1. Make sure the engine is in cold condition.
  2. Make sure that the unit for which you are going to take clearance should be in TDC. But generally, there are more than 6 units in a marine four-stroke engine. So at the same, flywheel will show two unit at TDC. To make sure the particular unit is at the compression stroke and not at the power stroke. The one with the free push rod of both units is at compression stroke and the one with tight push rod is at power stroke. So avoid the one which is at power stroke.
  3. Use appropriate thickness filler gauge as mentioned in the makers manual. Gently try to push the filler gauge between the clearance of the valve and rocker arm.

  1. Now you the clearance is more or less. Now comes the adjustment part. You need to open the nut on the rocker arm. After opening, you can adjust the clearance.
  2. Keep the filler gauge between the rocker arm and clearance of the valve at all time to get the perfect clearance.
  3. NOTE: When you move the filler gauge while adjusting for particular clearance, you should be able to slide smoothly (not too tight & not too loose).
  4. After adjustment, tighten the nut with given torque.


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