Zephyr "short" spark plugs

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This topic contains 6 replies, has 4 voices, and was last updated by Avatar garry-in-tampa 1 month ago.

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  • todd281
    todd281
    US Member - 1 Year
    Replies: 58
    Topics: 23
    #181578

    I’ve been searching forums all morning for advise on replacement plugs for a 4404 Zephyr. I would like to replace them with a shorter plug to allow more clearance between the cover and the plug . However I am seeing allot of different answers to which plug to use. I would like to stay with the screw on terminals [like NGK plugs have] so which plugs do I want? thanks for all the help so far.

    Tubs
    Tubs
    US Member - 1 Year
    Replies: 2359
    Topics: 141
    #181600

    I have used the CHAMPION J17LM in a Ranger, Scout, Cub
    and this summer in a Martin 75 after one plug shorted out
    through the boot to the tank. They seem to be the heat range
    for the oil and mix I use in these motors.

    todd281
    todd281
    US Member - 1 Year
    Replies: 58
    Topics: 23
    #181601

    So far my research has turned up that the recommended replacement was champion j-10 , the replacement for that plug is champion j6c. the j6c is a longer overall length .[about 2 inch] I am looking for a shorter overall length plug [like the one in a small chainsaw or weed-wacker] Something like a champion cj6y . I have seen references on the forum about using “shorty” plugs for the Zephyr because of the cover on the motor being so close to the plug terminal ends . I am unsure of the length of the J17LM plug but I think it is also one of the longer types. Thanks for the reply. Hopefully someone out here has the secret decoder ring , and can decipher if there is a short plug that will work in this . If not I will have to stay with the longer style.

    todd281
    todd281
    US Member - 1 Year
    Replies: 58
    Topics: 23
    #181608

    OK after some more digging in the forum I think I found a answer . One of the members suggested NGK plugs BM6A or BM7A replacements to correct this very problem . Thanks for the help.

    squierka39
    squierka39
    US Member - 2 Years
    Replies: 315
    Topics: 20
    #181614

    You said you like the screw on tops so I’m guessing you use a connector that fits under it. If so, Brillman has the thumbscrew type tops in metric for new plugs. They are a bit shorter than the long stock screw on piece. That might be just enough to help.

    todd281
    todd281
    US Member - 1 Year
    Replies: 58
    Topics: 23
    #181655

    Brillman I Googled it, allot of interesting stuff . I would like to get brass thumbscrew type ends. thanks

    • This reply was modified 1 month ago by todd281 todd281.
    Avatar
    garry-in-tampa
    Lifetime Member
    Replies: 3146
    Topics: 30
    #181668

    The original J10 commercial J was changed (renamed) J6-J around 1946. These became J6-C when they went to a solid copper center electrode. The short plugs are the same number with a preceding C, ie. CJ6-C. From the 1949 Champion catalog – Note the C7 is a hotter plug than the 7 – later books are fuzzy on this distinction. Factory recommendations are not etched in stone. running conditions vary. check the look of the insulator. Adjust to the heat range that matches your running condition.

    Garry in Michigan

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