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  1. #1
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    1988 Johnson 120 running rough, VERY rough

    CJ120 TLCCA serial#C 8237993

    The last time out, I arrived at the boat ramp only to discover that something had been left on and the cranking battery was totally drained dead. In a desperate attempt to save the trip, hooked up my battery booster and got the motor started. After running at idle for just a couple minutes the running lights became dim and I couldn't keep the motor running. Next trip to the lake I double checked that all batteries are fully charged, start her up and now its running really rough. Almost like its only running on 2 cyls. It won't idle without giving some gas or choke.
    The only thing i've done so far is pull out each spark plug. They all looked the same and they where just wet looking.

    Any ideas what I did to it? Power pack maybe? I'm kinda cluless.

    Thanks for reading my post.



  2. SC Club Moderator ChampioNman's Avatar
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    #2

    Re: 1988 Johnson 120 running rough, VERY rough (Fishaholic)

    Pack or timer base.

  3. Member
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    #3

    Re: 1988 Johnson 120 running rough, VERY rough (ChampioNman)

    Is there an easy method for a D.I.Y to check those things?



  4. Member
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    #4

    Re: 1988 Johnson 120 running rough, VERY rough (Fishaholic)

    I replaced the power pack and everything is back to normal. She runs like a sewing machine.
    A big thanks to ChampioNman for recommending the aftermarket power pack. It saved me almost $100.



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    #5

    Re: 1988 Johnson 120 running rough, VERY rough (Fishaholic)

    Championman to the rescue

  6. Sprint Boats Moderator Bassmeister's Avatar
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    #6

    Re: 1988 Johnson 120 running rough, VERY rough (chuck21)

    Glad Fred helped ya, I would have bet on the rectifier.

  7. Member
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    #7

    Re: 1988 Johnson 120 running rough, VERY rough (Bassmeister)

    I guess I counted my chickens before they hatched. It seemed to run smooth and idled good on the hose, but I took it to the lake and its still missing badly. What's the proceedure for checking the timmer base?



  8. SC Club Moderator ChampioNman's Avatar
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    #8

    Re: 1988 Johnson 120 running rough, VERY rough (Fishaholic)

    IM sent.

  9. Member
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    #9

    Re: 1988 Johnson 120 running rough, VERY rough (ChampioNman)

    IM recieved. Thanks again ChampioNman

    Here it is in case someone else searches this topic.

    (5:04 PM 7/28/2008) ChampioNman: Yep you need an ohm meter. attach black meter lead to port timer base connector E terminal. Attach red meter lead to each terminal on the starboard connector each reading must show 130 ohms +/- 30 ohms.
    Now attach red lead to each terminal on port connector. meter must show 45 ohms +/- 10 ohms. Any deviation replace timer base.
    Checks for grounded condition attach black lead to ground and touch each terminal on both connectors. If a short is indicated on any terminal repair short or replace timer base.
    Set meter to the appropriate ohm scale, tests must be performed with power off.




  10. Member
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    #10

    Re: 1988 Johnson 120 running rough, VERY rough (Fishaholic)

    I decided to go ahead and try a new set of Champions and then confirm whether I'm getting spark at each cylinder.

    I DID get a good spark at each cyl. and it seems to run much better on the hose with the new plugs. Its kind of hard to tell at this point whether or not its fixed. I will take it to the lake asap to find out for sure.

    If my timer base was no good, or a after market power pack was no good, could I still get a spark on all 4 cyls.?
    These old 2 strokes are confusing.



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