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  1. #1

    Default 68 Johnson 9.5 HP

    Hey just bought this thing from a backyard mechanic

    The motor hesitates at very low idle

    But runs nice at higher rpms

    Can you spot the problems?


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    Last edited by 909; 07-21-2021 at 05:02 PM.

  2. #2

    Default Re: 68 Johnson 9.5 HP

    Attachment 27467

    Attachment 27468

    Here's a short clip of the motor running

    https://streamable.com/zqxvv0

    Feedback welcome
    Last edited by 909; 07-21-2021 at 05:03 PM.

  3. #3
    Join Date
    Sep 2010
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    Default Re: 68 Johnson 9.5 HP

    Sounds like it might be running on 1 cylinder.-----Compression test needed.----Post the values.----Check spark.-----Good spark on those can easily jump a gap of 5/16" on a test device.----Other than that I see a 9.5 HP motor in the pictures.----Looks just like other 9.5 HP motors.-----Worked on lots and have a bunch of parts motors.

  4. #4
    Join Date
    Nov 2011
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    3,385

    Default Re: 68 Johnson 9.5 HP

    Where's a video of it hesitating at slow idle? That motor has been overheated at some time in it's life. May or may not have anything to do with it.

  5. #5

    Default Re: 68 Johnson 9.5 HP

    Quote Originally Posted by racerone View Post
    Sounds like it might be running on 1 cylinder
    How can you tell from the video ? Can you show me how it should sound ?


    Quote Originally Posted by fdrgator View Post
    Where's a video of it hesitating at slow idle? That motor has been overheated at some time in it's life. May or may not have anything to do with it.
    I'm working on another low idle video. How can you tell it's been overheated ?

  6. #6

    Default Re: 68 Johnson 9.5 HP


  7. #7
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    Sep 2010
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    Default Re: 68 Johnson 9.5 HP

    See post #3-----Worked on these motors when they were new !

  8. #8
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    Nov 2011
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    3,385

    Default Re: 68 Johnson 9.5 HP

    Quote Originally Posted by 909 View Post
    How can you tell from the video ? Can you show me how it should sound ?




    I'm working on another low idle video. How can you tell it's been overheated ?
    Paint is scorched on the cylinder head and exhaust manifold.

  9. #9

    Default Re: 68 Johnson 9.5 HP

    Quote Originally Posted by fdrgator View Post
    Paint is scorched on the cylinder head and exhaust manifold.
    Could that possibly be dirt ?

  10. #10

    Default Re: 68 Johnson 9.5 HP

    Quote Originally Posted by racerone View Post
    Compression test needed.----Post the values.----Check spark.-----Good spark on those can easily jump a gap of 5/16" on a test device
    I don't have the tools to do a compression test

    Here's an updated video

    https://streamable.com/899wbv

    What do you think ?

  11. #11
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    Default Re: 68 Johnson 9.5 HP

    Looks like testing is done near Toronto.----Seems to sound a little better now.

  12. #12

    Default Re: 68 Johnson 9.5 HP

    Yes. I'm from downtown Toronto.

    And took her for a spin around the Toronto islands ( Center Island )

    I haven't done anything to it yet.

    Just pulled and cleaned the plugs and tightened the fuel lines.

    I heard these motors typically go 8-12 mph (12-19 kmh )

    Is there anything else I can do to improve performance ?

  13. #13
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    Sep 2010
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    Default Re: 68 Johnson 9.5 HP

    The inflatable boats present more drag.---A 12' aluminum would be faster.

  14. #14

    Default Re: 68 Johnson 9.5 HP

    Aside from buying a new boat

    Can I do anything to the motor to make it run faster

  15. #15
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    Sep 2010
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    Default Re: 68 Johnson 9.5 HP

    See if you can find a shop in the GTA that has a TEST PROPELLER.-----You could test the motor and see if it is actually putting out the power as built in Peterborough.

  16. #16

    Default Re: 68 Johnson 9.5 HP

    Thanks can you recommend any shops, preferably someone who won't try to rip me off

    Is there anything I can do to myself improve efficiency or performance maintenance wise

  17. #17
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    Sep 2010
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    Default Re: 68 Johnson 9.5 HP

    Sorry-----You already questioned the expertise of someone with years of experience elsewhere.( Florida ) I believe.----I also own about 10 of these motors 3 hrs away from you.----Not going to risk giving you advice on your motor or where to take it.-----Call around and see what help you can find.

  18. #18
    Join Date
    Oct 2019
    Location
    Lake Simcoe, Ontario, Canada
    Posts
    108

    Default Re: 68 Johnson 9.5 HP

    For reference, my 61 10hp pushes my 16 foot tinny with my wife and I on board to 23 kph.
    And neither of us are skinny people...
    James in Canada

    4W75A
    10022
    E115TLCIM

    If it aint broke, Try Harder!

  19. #19

    Default Re: 68 Johnson 9.5 HP

    Quote Originally Posted by James in Canada View Post
    For reference, my 61 10hp pushes my 16 foot tinny with my wife and I on board to 23 kph.
    And neither of us are skinny people...
    There's much more drag with the soft bottom 10 ft Zodiac. So far we hit 16 kph

  20. #20
    Join Date
    Jul 2020
    Location
    Virginia, MN
    Posts
    128

    Default Re: 68 Johnson 9.5 HP

    Quote Originally Posted by racerone View Post
    Sorry-----You already questioned the expertise of someone with years of experience elsewhere.( Florida ) I believe.----I also own about 10 of these motors 3 hrs away from you.----Not going to risk giving you advice on your motor or where to take it.-----Call around and see what help you can find.
    Not sure how asking a question could hurt? Didn't seem to be ment in a harsh way from my end.

    To the OP, from your second video it sounds better. But check your spark, compression first. Second check things visually to see if things look right. IE, no bent of sticky linkage, wires that are cracking, fuel lines that are sorta kinked. Other than that if things check out, you should have a good runner. Those old 9.5s weren't barn burners, but they did what they were designed to do. If you want more hp buy a 9.9 and do the 15hp conversion on it. I finished mine and I am very thrilled. A 1975 Johnson 9.9, that acts a bit bigger. But still idles as smooth as can be, loads of low end torque, and revs nice. I am looking for a 9.5 for a project as we speak, but covid has people money goofy now.

  21. #21
    Join Date
    Oct 2019
    Location
    Ontario Canada
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    Default Re: 68 Johnson 9.5 HP

    Quote Originally Posted by BRUPP79 View Post
    . I am looking for a 9.5 for a project as we speak, but covid has people money goofy now.
    Brupp where are you?
    Here in Canada, those 9.5s are listed every week, with statements such as, “maybe needs a carb job”, ran well last season, won’t start now”.
    They can be had for $150-$250, that’s around $200USD.
    I’ve never persued them, as it is easier, cheaper, & better resale value on the newer types.

  22. #22
    Join Date
    Oct 2019
    Location
    Ontario Canada
    Posts
    133

    Default Re: 68 Johnson 9.5 HP

    Just looking quickly, here are a few 9.5ís, these come from short season, low hours, the ines that run are only $400, ($300US).
    https://www.kijiji.ca/v-powerboat-mo...400/1569251403
    https://www.kijiji.ca/v-powerboat-mo...tor/1572143046
    https://www.kijiji.ca/v-powerboat-mo...tor/1577945009
    look at that last one, clean as a whistle, itís a Ď79, includes tank & hose. $300 CDN...OBO, probably $200 cash buys it, thatís $170 US.

  23. #23
    Join Date
    Jul 2020
    Location
    Virginia, MN
    Posts
    128

    Default Re: 68 Johnson 9.5 HP

    Quote Originally Posted by Edchris177 View Post
    Brupp where are you?
    Here in Canada, those 9.5s are listed every week, with statements such as, “maybe needs a carb job”, ran well last season, won’t start now”.
    They can be had for $150-$250, that’s around $200USD.
    I’ve never persued them, as it is easier, cheaper, & better resale value on the newer types.
    Just about 2 hrs south of Fort Frances. There are one of two close by that are close to my price range. I am admitably a cheap skate!

  24. #24

    Default Re: 68 Johnson 9.5 HP

    Good deals can be had if you're willing to drive 2-3 hours from your location. $100-$200 for motors that need work and $300-$400 for running motors

    Here's a video of carb cleaning the high speed jet:

    https://streamable.com/qrx0eh

    There's a small hole squirting out carb cleaner on the opposite side of the high speed jet to the exterior

    A friend says this isn't normal and says there should be a mixing screw there

    Is he wrong ?
    Last edited by 909; 07-26-2021 at 11:04 PM.

  25. #25

    Default Re: 68 Johnson 9.5 HP

    Here's a video of the motor play

    https://streamable.com/f7qqvy

    Does this look OK ?

  26. #26

    Default Re: 68 Johnson 9.5 HP


  27. #27
    Join Date
    Sep 2010
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    22,482

    Default Re: 68 Johnson 9.5 HP

    Broken motor mount.------That might pull choke on at full throttle.

  28. #28

    Default Re: 68 Johnson 9.5 HP

    Thanks. Would a proper working mount be stiff and rigid, behaving exactly like the opposite side ?

  29. #29

    Default Re: 68 Johnson 9.5 HP

    Which mount is broken?

  30. #30
    Join Date
    Sep 2010
    Posts
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    Default Re: 68 Johnson 9.5 HP

    I am not there looking over your shoulder or looking at your motor.----I can only go by what you say or show.----Inspect the front mount.

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