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  1. #1
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    Bunch of problems in Johnson GT300

    Hi,

    Engine starts sometimes with all cylinders but when you start taking it to the plane it drops one cylinder off and it stays like that. All revs stops in 2200rpm with gear on. With neutral it sometimes gets full revs after turning key off and on.
    Yesterday i also noticed that it wont charge anymore and that was a new problem. I have worked all ****in summer to get motor scream but no no no.......first i cleaned all carbs because it seemed that it was gasoline problem and ofcourse there can be that problem too still...everything has been cleaned and onetime.it has been on plane and worked 10min, then everything off stopped and started after 5mins. Have changed plugs, checked spark, checked coils, checked leaks on gasoline side but no, it will ****in limb all the time.
    I also added electric gas pump to make sure it gets gasoline because it one time worked fully when i drove and buddy pumped with the bulp....
    Please give me some advises🤷*♂️

  2. #2
    Join Date
    Apr 2001
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    Cardington Ohio
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    Link and sync.
    I'd rather be competitive w/junk I built in my garage than win w/stuff I bought.


    I refuse to allow common sense to interfere w/my boat buying decisions.


    Checkmate 16' 140 Johnson
    Hydrostream 17' Vector FrankenRude I
    Laser 480 (?) 21' w/GT 200
    Glastron Carlson Conquest w/XP 2.6
    Glastron Carlson CVX 20 w/XP 2.6
    24' Sonic w/twin 250 Johnsons
    24' Sonic w/twin 250 HO Johnsons
    19' STV River Rocket w/FrankenRude II
    Allison XR 2002 w/Frankenrude II
    Hydrostream 18' V-King w/Frankenrude II

  3. #3
    Join Date
    May 2002
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    Lake Havasu City AZ
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    Make sure your shift linkage is set correct. I have had the shift interrupter cause the engine to drop 4 cylinders.

  4. Likes David - WI, Baker343, racer, rgsauger liked this post
  5. #4
    Join Date
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    aalsmeer
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    Maybe start with a fresh set of spark plugs when it runs
    You might be able to see what the problem cylinders are and search more focused
    NGK BR8-HS10

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