Results 1 to 7 of 7
  1. #1

    Default "the motor starts and runs fin

    "the motor starts and runs fine but when i open it up to full throttle it starts to take off and then shuts down to about half power. it will jump to full power every once in a while and sometimes when it does this it will stay at full power until you throttle it back down. i have replaced the coils, points, and condensers and im not sure what else to do?"

  2. #2
    Join Date
    Oct 2007
    , ny, us

    Default "Sounds like one of the cylind

    "Sounds like one of the cylinders is not firing under certain conditions. When it goes to half power, let it run for a few minutes and then feel the temperature of each cylinder head. The non firing cylinder should be noticeably cooler. If that is the case, then check that cylinder for spark. Usually an ignition problem but several other possibilities. One on the water test would be to temporarily gap the plug to about .010. If the cause is a weak spark, this will put less demand on the system and if the motor then runs normally, you have found the problem."

  3. #3

    Default 1975 70hp johnson have only ha

    1975 70hp johnson have only half power at full throttle been running great put up for winter took out and now just half power something sticking?

  4. #4
    Join Date
    Apr 2006
    , Langkawi, Malaysia

    Default Dan. More likely a clogged ma

    More likely a clogged main jet in one of the carbs.

  5. #5

    Default do i need to take apart or can

    do i need to take apart or can I spray cleaner in carb?

  6. #6
    Join Date
    Feb 2001
    Central West Florida

    Default "Take it apart, clean and rebu

    "Take it apart, clean and rebuild it.

    Spraying cleaner into a carb is a waste of time. It simply goes thru the carb throat and into the crankcase..... not into the carburetor passageways.

    Thousands of parts in my remaining stock. Not able to list them all. Let me know what you need and I'll look it up for you. Visit my eBay store at:

    We occasionally have questions. If you fail to answer, it may affect ours.

  7. #7
    Join Date
    Apr 2006
    , Langkawi, Malaysia

    Default "You may get away by taking ou

    "You may get away by taking out the drain plug in the float bowl and then with a screwdriver remove the main jet, but the best and safest it what Joe describes. Following Joes's advice You need the repair kit at hand. My suggestion is more a 'band aid' attempt."

Similar Threads

  1. 87 Johnson 60 HP missingno power at full throttle
    By muley99 in forum Johnson Evinrude Outboard Archive
    Replies: 6
    Last Post: 11-02-2009, 09:12 PM
  2. Losing power full throttle
    By nicolesmith in forum OMC Sterndrive and Inboard Archive
    Replies: 7
    Last Post: 07-29-2008, 04:05 PM
  3. Replies: 2
    Last Post: 02-20-2006, 08:11 PM
  4. 1974 85hp Johnson slow power and stalls at full throttle
    By Mark Hayes in forum Johnson Evinrude Outboard Archive
    Replies: 5
    Last Post: 04-10-2004, 11:06 AM
  5. 1975 Johnson 115 HP Looses power at Full throttle
    By roger in forum Outboard motors archive 2000-2004
    Replies: 1
    Last Post: 09-09-2001, 09:23 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts