Help Troubleshooting: 440 and 550 won't start when hot unless throttle opened fully - Page 2
pxctoday

» Log in

User Name:

Password:

Not a member yet?
Register Now!

» Find OEM Parts

» Jobs

» wallpapers

Page 2 of 2 FirstFirst 12
Results 11 to 14 of 14
  1. #11
    PWCToday.com Is My Home Away From Home wmazz's Avatar
    Join Date
    Jul 2013
    Location
    Riverside, CA
    Age
    61
    Posts
    2,968
    Blog Entries
    6

    Re: Help Troubleshooting: 440 and 550 won't start when hot unless throttle opened ful

    Quote Originally Posted by manytoyman View Post
    UPDATE:
    after watching these carbs when the motor is turned off I discovered that both of them feed fuel (or air) backwards
    from the return line through the carb and back to the tank. Given 15 seconds or more they fill with air. I can see this in the fuel lines.
    There is supposed to be a restriction in each carbs return line.
    Each carb is nearly plugged off at idle because the restriction
    is only .013".

    But if your 440 has a 38mm 550 carb, the restrictor is missing.

    There is no restrictor in the 44mm 559 carb either.

    On both of the 550 carbs (38's and 44's) the restrictor is on the right
    hand side of the hull.

    The purpose of the restriction is to prevent the engine from
    running rich at idle. Otherwise the return line is not needed.

    After idle the engine consumes more fuel, and less (if any) gas
    returns to the tank.


    Bill M.
    Horsepower == Speed, RPM != Speed



  2. #12
    PWCToday Regular
    Join Date
    May 2008
    Location
    VA
    Posts
    64

    Re: Help Troubleshooting: 440 and 550 won't start when hot unless throttle opened ful

    Thanks Bill. I needed to be more clear.
    The 85 440 has the OEM 38mm Mikuni carb that came with it.
    The 88 550 has the OEM 44mm Mikuni carb that came with it and rev limiter is present but I have not tested it.
    Question: is there a standard way of testing the restrictor in the 440s 38mm carb?
    I know I can blow air through the rev limiter to test the 550 and will do that shortly.

    Jim

  3. #13
    PWCToday.com Is My Home Away From Home wmazz's Avatar
    Join Date
    Jul 2013
    Location
    Riverside, CA
    Age
    61
    Posts
    2,968
    Blog Entries
    6

    Re: Help Troubleshooting: 440 and 550 won't start when hot unless throttle opened ful

    The return line on the 38bn 440 & 550 uses a banjo bolt for the restrictor.

    Remove the banjo bolt, and turn it upside down. Either there will be a small
    hole for the restrictor, or about a 1/8" hole for the 550 style 38.

    I know you said the 38bn was the original 440 carb, but from the outside
    they are the same, except there is a 1/8" hose fitting near the top right
    of the carb for the 550 rev-limiter.


    Bill M.

    I believe the restrictor size is stamped on the top of the banjo bolt.
    Horsepower == Speed, RPM != Speed



  4. #14
    PWCToday Regular
    Join Date
    May 2008
    Location
    VA
    Posts
    64

    Re: Help Troubleshooting: 440 and 550 won't start when hot unless throttle opened ful

    UPDATE: took the 550 out yesterday for a test with the one way check valve mounted in the tank on the RES line. Perfect. Ski starts and idles now when hot. So if you have a hard staring ski when hot it might be worth a try. Certainly worked for me. The 440 is now starting fine on the trailer after installing a check valve in it as well. Will test this one when the river comes back down (rising from 4 to 20 ft due to hurricane remains coming through the area).

Page 2 of 2 FirstFirst 12

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Powered by vBadvanced CMPS v4.2.0