Logo
Results 1 to 5 of 5
  1. #1

    Default 1994 150 HP johnson questions

    I have a 1994 Johnson 150 HP Model J150EXERV---Having trouble with starting and carb flooding. I have a few questions I hope someone can answer. I rebuilt the six carbs with new gaskets and float needle/seats. etc. Bowls were warped so sanded them flat and adjusted floats etc. seems to me the needles should be able to stop the flow of fuel when the bulb is pumped however carbs are dripping fuel out the intake on most all of them if I pump the bulb. Can the bulb overpower the float needles or is fuel getting past the thin squiggly gasket that is embedded in the carb body backside and flowing into the carb throat?
    My other question is---All the carbs have a vacuum port tube mounted on the body backside. These are all uncapped and open to the air. Doesn't this cause a vacuum leak into the intake? How does this not mess up the mixture?

  2. #2
    Join Date
    Sep 2010
    Posts
    24,219

    Default Re: 1994 150 HP johnson questions

    deleted

  3. #3
    Join Date
    Nov 2005
    Location
    Mt. Zion, Illinois,
    Posts
    1,198

    Default Re: 1994 150 HP johnson questions

    When adjusting fuel floats you need to turn the carb upside down and let the float lay in the closed position. Holding the carb level and looking from the side, you should see a slight rise in the float from the hinge side (lower) to the far end (slightly higher.) I forget the exact measurement, but maybe 0.030" or so.

  4. #4

    Default Re: 1994 150 HP johnson questions

    Quote Originally Posted by kevinj View Post
    When adjusting fuel floats you need to turn the carb upside down and let the float lay in the closed position. Holding the carb level and looking from the side, you should see a slight rise in the float from the hinge side (lower) to the far end (slightly higher.) I forget the exact measurement, but maybe 0.030" or so.
    Hi---Thanks for the info---already adjusted floats according to this instruction. My question is-- can the primer bulb force fuel past the float needle when the bowl is full? Doesn't seem like it should be able to push fuel past six closed float needles !! My current theory is fuel may be getting pushed past the thin o-ring type gasket between the carb body and throttle body. It would only need to breech a 1/32" fine line of o-ring to spray into the carb throat and drip out the front. Also the back side of these old carbs could be warped between the bolts creating a poor seal with the throttle body. The other thing folks should to watch for is the aftermarket replacement float bowl gaskets are of a material that has shrunk over the winter and does not take the shape of the top of the float bowl but in fact stretches almost straight between the screw holes and protrudes into the float chamber possibly contacting and hindering the movement of the float.I Have new gaskets on order from a different company and will see if this helps.
    My other question is about the vacuum ports on the back plate of these carbs. They are for carb balancing but shouldn't they be capped off most of the time?

  5. #5
    Join Date
    Nov 2011
    Location
    tennessee
    Posts
    5,484

    Default Re: 1994 150 HP johnson questions

    Did you install the thin plastic washers under the inlet needles?
    Pappys Sales and Service
    Owner and Factory Certified Technician
    Former racer KDBA (Kentucky Drag Boat Association)

Similar Threads

  1. 1994 OMC 50 hp cooling system questions
    By ssherbundy in forum Johnson Evinrude Outboard Forum
    Replies: 7
    Last Post: 05-17-2020, 11:04 AM
  2. 1994 150 xri questions concerning rpms
    By Msdavis in forum Fuel Gas Oil Mixture Ratio
    Replies: 0
    Last Post: 03-31-2020, 02:33 PM
  3. 1994 Johnson 4 hp seahorse /Generic questions
    By Coquinick in forum Johnson Evinrude Outboard Forum
    Replies: 2
    Last Post: 11-02-2017, 08:12 PM
  4. 1994/5 M5B - troubleshooting/questions
    By s2sailorlis in forum Nissan Tohatsu Outboard Forum
    Replies: 4
    Last Post: 12-05-2014, 05:21 PM
  5. 1994 90hp Merc questions
    By navchapdoc in forum Mercury Mariner Outboard Archive
    Replies: 2
    Last Post: 08-16-2008, 08:51 AM

Posting Permissions

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