Cub Cadet FAQ's

Spark Plug Table

Thanks to David Kirk for researching and presenting this information.

Engine – Kohler K241 (10 HP), K301 (12 HP), K321 (14 HP), K341 (16 HP)

Manufacturer and Number                                                     Mfgr. Stock Number

Champion H10C                                                                     844
Accel 168                                                                               
AC Delco M44L
Autolite 216
Bosch W9AO
Denso W14L                                                                           6013
Motorcraft AL5
NGK B4L                                                                               3112
Prestolite 14L7                                                                       
Splitfire SF21F

 Notes: 14mm, 7/16 reach, 13/16 hex.  These plugs recommended for stock engines. 

                                                                                                           
Engine* – Kohler K241 (10 HP), K301 (12 HP), K321 (14 HP), K341 (16 HP)

Manufacturer and Number                                                     Mfgr. Stock Number
Champion H8C                                                                       587
Accel 166                                                                               
AC Delco CR43L
Autolite 494
Bosch ---
Denso W16LS                                                                       
Motorcraft ATL4
NGK B6L                                                                              
Prestolite 14L4                                                                       
Splitfire ---
 

Notes: 14mm, 7/16 reach, 13/16 hex. 

*These are colder heat range plugs for use in modified engines with higher than stock compression ratios.                                                                                                           
Engine – Kohler K141 (6.25 HP), K161 (7 HP), K181 (8 HP)

 Manufacturer and Number                                                     Mfgr. Stock Number

Champion J8C                                                                        841
Accel ---                                                                                 
AC Delco 44
Autolite 458
Bosch W8EC
Denso W16SU                                                                       
Motorcraft A5
NGK B6S                                                                              
Prestolite 14-5                                                                        
Splitfire SF29E

 Notes: 14mm, 3/8 reach, 13/16 hex. 

 Engine – Kohler KT17 Opposed Twin

 Manufacturer and Number                                                     Mfgr. Stock Number

Champion RV17YC                                                               25
Accel 577                                                                               
AC Delco CR44TS
Autolite 27
Bosch ---
Denso TR14PRU                                                                   
Motorcraft ARF62
NGK ---                                                                                 
Prestolite 14RF62                                                                  
Splitfire ---
 

Notes: 14mm, .460 reach, 5/8 hex. 
Engine – Onan 20 HP Opposed Twin

Manufacturer and Number                                                     Mfgr. Stock Number

Champion RC14YC                                                               431
Accel ---                                                                                 
AC Delco FR4LS
Autolite 3926
Bosch ---
Denso ---                                                                                
Motorcraft ---
NGK FR5                                                                              
Prestolite ---                                                                           
Splitfire ---

 Notes: 14mm, 3/4 reach, 5/8 hex.