SER FAQ: LMFAQ: Typical mechanical specifications

S.E.R. FAQ

NotTaR of small Gasoline Engines and Rotary Lawn Mowers : Typical torque specifications
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Typical torque specifications

For proper operation and long life, you cannot just tighten critical nuts and bolts by feel. You really don't want the connecting rod cap to come loose while the engine is running! The following are just samples - check your engine manual for exact values!!! The most critical are the connecting rod bolts or nuts and the cylinder head bolts.

     Location                    Torque ---> Inch-pounds    Foot pounds  
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Cylinder head bolts:                          160 - 200       13 - 16

Connecting rod bolts (Durlock rod bolts):

      2.5 - 4 HP small frame:                  96 - 110      7.9 - 9.1
        5 - 6 HP medium frame:                130 - 150     10.8 - 12.5
        7 - 10 HP medium frame:               150 - 170     12.5 - 14.1

Cylinder cover or flange to cylinder:          65 - 110      5.5 - 9.0

Flywheel nut:                                 360 - 396       30 - 33

Spark plug:                                   180 - 360       15 - 30

Magneto stator to cylinder:                    40 - 90       3.3 - 7.5

Starter to blower housing or cylinder:         40 - 60       3.3 - 5.0

Housing baffle to cylinder:                    48 - 72         4 - 6

Breather cover to cylinder:                    20 - 26       1.7 - 2.1

Intake pipe to cylinder:                       72 - 96         6 - 8

Carburetor to intake pipe:                     48 - 72         4 - 6

Air cleaner to carburetor (plastic):            8 - 12           1

Tank plate to bracket (plastic):              100 - 144        9 - 12

Tank to housing:                               45 - 65       3.7 - 5

Muffler bolts to cylinder:

       1 - 5 HP small frame:                   30 - 45       2.5 - 3.5
       4 - 5 HP medium frame:                  90 - 150        8 - 12

Electric starter to cylinder:                  50 - 60         4 - 5

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