What size tap do I need for ….

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This topic contains 11 replies, has 5 voices, and was last updated by Avatar lyks2tinkr 1 week, 1 day ago.

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    huntleybill
    US Member - 1 Year
    Replies: 224
    Topics: 85
    #181054

    I have a mid 70’s Evinrude 2HP motor that the idle needle threads on the carb side are damaged and I can’t screw the needle in. Can someone please tell me what size tap I need to chase those threads?

    Thank you
    Bill

    Mumbles
    Mumbles
    Canada Member - 2 Years
    Replies: 4152
    Topics: 421
    #181056

    If you can wait a while I can measure one when I get back later.

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    huntleybill
    US Member - 1 Year
    Replies: 224
    Topics: 85
    #181090

    ok… waiting

    Mumbles
    Mumbles
    Canada Member - 2 Years
    Replies: 4152
    Topics: 421
    #181092

    Sorry. Got home late. Will check first thing in the AM.

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    gbm
    US Member - 1 Year
    Replies: 68
    Topics: 9
    #181096

    Most tap ad die sets have a thread gauge for every size in the set. They are also available separately. Measure the needle.

    Sufficiently advanced technology is indistinguishable from magic

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    huntleybill
    US Member - 1 Year
    Replies: 224
    Topics: 85
    #181112

    Thanks gbm, but that is only half the dimension size. I “think” it is a 40 threads per inch but how big is it?

    Mumbles
    Mumbles
    Canada Member - 2 Years
    Replies: 4152
    Topics: 421
    #181134

    Dang it Bill but I’ve been searching and can’t find the carb. I know it’s here somewhere as the motor is fully rebuilt and waiting for paint.

    I’ll keep looking until I find it. Sorry for the wait.

    Mumbles
    Mumbles
    Canada Member - 2 Years
    Replies: 4152
    Topics: 421
    #181213

    I looked all over and still can’t find that two horse carb but other ones from that era, such as 9.9 and an early 80’s 4.5 I found, have a 1/4 X 28 thread on the low speed needle. That’s a common SAE fine thread so no special tap or dye needed.

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    huntleybill
    US Member - 1 Year
    Replies: 224
    Topics: 85
    #181215

    Thanks mumbles but I have a 1/4-28 and it is too course. I have a 4-40 tap that the threads fit and the shaft of the needle is 1/4″. I have never heard nor can I find a 1/4-40 tap. What am I missing?

    Mumbles
    Mumbles
    Canada Member - 2 Years
    Replies: 4152
    Topics: 421
    #181216

    I posted some special taps and dies used on OMC motors over on the Facebook site and a 1/4 X 40 was one of them. I had to order mine from a tool house in Vancouver. Grainger or someplace like them might be able to supply them or maybe on Ebay.

    If you Google that size you should get some hits.

    • This reply was modified 1 week, 2 days ago by Mumbles Mumbles.
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    dave-bernard
    US Member - 2 Years
    Replies: 876
    Topics: 10
    #181239

    I got one on Ebay
    used on control cables in the 50’s 60’s .

    • This reply was modified 1 week, 2 days ago by Avatar dave-bernard.
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    lyks2tinkr
    US Member - 1 Year
    Replies: 277
    Topics: 34
    #181242

    1/4 40 should be able to be had without a lot of trouble. 50s OMC used that size on their carb needles.

    • This reply was modified 1 week, 1 day ago by Avatar lyks2tinkr.
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