Results 1 to 15 of 15

Thread: H Type Carburetors BN2 M version Leaking Fuel At Jet Bearing Area

Forum to discuss Austin Healey Sports Cars

  1. #1
    Senior Member Martinld123's Avatar
    Join Date
    Jan 2012
    Location
    The Villages, Fl
    Posts
    92
    Blog Entries
    1
    Thanks Thanks Given 
    0
    Thanks Thanks Received 
    0
    Thanked in
    0 Posts

    H Type Carburetors BN2 M version Leaking Fuel At Jet Bearing Area

    My H type Carb M version is leaking fuel at Jet bearing area. This "M" carb is only about three years old that I bought new from Moss. Too soon for three year old new carb to be leaking fuel I think. I had rebuilt my old M carbs so I can do it but hoping for a shortcut instead of pulling carb, air-box, etc, off engine. If it is the cork sealing ring I think I can do work in place? I have an older unused cork sealing ring soaking in oil right now. That has to be problem area, right?

    Another note: I lose oil in this (new) dash pot also. Unrelated I am sure. On my old M carbs I bought Moss no leak rubber replacement Gland washer at top of jet bearing area. Seemed like a great idea until I realized it caused choke to stick. Ended up putting cork gland washer back in. Anyone else had any experiences like this? Looks like this cork washer needs to be replaced also.

    Update: I am lost. It seems to be leaking fuel worse than ever after replacing two jet corks and one bottom ring sealing cork. Maybe I should not have soaked bottom sealing cork in oil over night? Leak has an oil color to the fuel smell. Dash pot? I think I will install new bottom ring cork dry and see if that might do it. If that is not it I will have to remove carb and look for a hair line crack in case. Any other ideas? Marty
    Last edited by Martinld123; 01-08-2020 at 05:23 PM.

  2. #2
    Yoda
    Join Date
    Feb 2007
    Location
    California USA
    Posts
    4,119
    Thanks Thanks Given 
    5
    Thanks Thanks Received 
    57
    Thanked in
    51 Posts

    Re: H Type Carburetors BN2 M version Leaking Fuel At Jet Bearing Area

    I think the only way to do it would be to attack from underneath, but I don't know if that's even possible. I think these seals--either rubber or cork--are going to leak sooner or later; maybe why SU went to diaphragm-type HDs?

    Did you grease the seals? I don't know if it's called-for, but it seems logical. FWIW, the HSes on my M weep a little fuel, but not so much I'm concerned (yet).

  3. #3
    Freshman Member
    Join Date
    Jul 2003
    Location
    Carpinteria,CA
    Posts
    23
    Thanks Thanks Given 
    0
    Thanks Thanks Received 
    0
    Thanked in
    0 Posts

    Re: H Type Carburetors BN2 M version Leaking Fuel At Jet Bearing Area

    In place of the cork gland washer I installed white Teflon O-rings TEF010 from the O-Ring store. Use 2 rings for each cork ring. Smooth and fuel tight
    C.G. Hart

  4. #4
    Jedi Hopeful
    Join Date
    May 2013
    Location
    Australia
    Posts
    124
    Thanks Thanks Given 
    1
    Thanks Thanks Received 
    2
    Thanked in
    2 Posts

    Re: H Type Carburetors BN2 M version Leaking Fuel At Jet Bearing Area

    Before doing anything too drastic it may be an idea to try nipping up what SU call the jet locking screw(s).

    This is actually a large hex under the base of the carb which holds the whole jet assembly tight. It has a large cork ring (originally) which may have shrunk a little. A bit awkward to get a spanner on with the linkage in place but should be do-able.

    Danny

  5. #5
    Yoda John Turney's Avatar
    Join Date
    May 2002
    Location
    Concord, CA
    Posts
    3,760
    Thanks Thanks Given 
    53
    Thanks Thanks Received 
    34
    Thanked in
    33 Posts

    Re: H Type Carburetors BN2 M version Leaking Fuel At Jet Bearing Area

    Quote Originally Posted by Dandare View Post
    ... nipping up ....

    Danny
    Does that mean tighten in American?
    John, BN4

  6. #6
    Jedi Hopeful
    Join Date
    May 2013
    Location
    Australia
    Posts
    124
    Thanks Thanks Given 
    1
    Thanks Thanks Received 
    2
    Thanked in
    2 Posts

    Re: H Type Carburetors BN2 M version Leaking Fuel At Jet Bearing Area

    Quote Originally Posted by John Turney View Post
    Does that mean tighten in American?
    Yes, but measured with caution

    Danny

  7. #7
    Senior Member Martinld123's Avatar
    Join Date
    Jan 2012
    Location
    The Villages, Fl
    Posts
    92
    Blog Entries
    1
    Thanks Thanks Given 
    0
    Thanks Thanks Received 
    0
    Thanked in
    0 Posts

    Re: H Type Carburetors BN2 M version Leaking Fuel At Jet Bearing Area

    Quote Originally Posted by Dandare View Post
    Before doing anything too drastic it may be an idea to try nipping up what SU call the jet locking screw(s).

    This is actually a large hex under the base of the carb which holds the whole jet assembly tight. It has a large cork ring (originally) which may have shrunk a little. A bit awkward to get a spanner on with the linkage in place but should be do-able.

    Danny
    M carb cork sealing ring.jpg

    Danny did this shrink a little, lol? Brand new "M" carb from Moss delivered from England about three years ago. This is how it came from the manufacturer. I think instead of putting in oil over night they just cut dry cork in half to fit! Who would do work like this? Marty

  8. #8
    Yoda steveg's Avatar
    Join Date
    Sep 2007
    Location
    Altadena, CA
    Posts
    3,906
    Thanks Thanks Given 
    104
    Thanks Thanks Received 
    167
    Thanked in
    143 Posts

    Re: H Type Carburetors BN2 M version Leaking Fuel At Jet Bearing Area

    I'd call Joe Curto. He's very responsive to issues like this and will have a definitive answer:

    http://joecurto.com/contact
    Steve Gerow
    Altadena, CA, USA
    Maker of most complete Big Healey rear disc kit
    Check out my galleries:
    http://www.pbase.com/stevegerow


  9. #9
    Jedi Hopeful
    Join Date
    May 2013
    Location
    Australia
    Posts
    124
    Thanks Thanks Given 
    1
    Thanks Thanks Received 
    2
    Thanked in
    2 Posts

    Re: H Type Carburetors BN2 M version Leaking Fuel At Jet Bearing Area

    Marty that is bizarre, looks like it is 47 years old.

    I would definitely check the seals on the jets as well...both carbs.

    Danny

  10. #10
    Senior Member Martinld123's Avatar
    Join Date
    Jan 2012
    Location
    The Villages, Fl
    Posts
    92
    Blog Entries
    1
    Thanks Thanks Given 
    0
    Thanks Thanks Received 
    0
    Thanked in
    0 Posts

    Re: H Type Carburetors BN2 M version Leaking Fuel At Jet Bearing Area

    Update: I am lost. It seems to be leaking fuel worse than ever after replacing two jet corks and one bottom ring sealing cork. Maybe I should not have soaked bottom sealing cork in oil over night? Leak has an oil color to the fuel smell. Dash pot? I think I will install new bottom ring cork dry and see if that might do it. If that is not it I will have to remove carb and look for a hair line crack in case. Any other ideas?

    When bottom ring is tight I can still tap side of jet and take it off of center for jet needle. That seems wrong to me. Marty

  11. #11
    Jedi Hopeful
    Join Date
    May 2013
    Location
    Australia
    Posts
    124
    Thanks Thanks Given 
    1
    Thanks Thanks Received 
    2
    Thanked in
    2 Posts

    Re: H Type Carburetors BN2 M version Leaking Fuel At Jet Bearing Area

    Marty, this may come down to quality of parts.

    If the new sealing cork you show in the picture a couple of posts back is the one you are installing, then it looks a bit cheap & nasty to me. The good cork ones are made from a sort of (what I call) neoprene cork. You can see this material in a lot of flat sheet type gasket material.

    Danny

  12. #12
    Yoda
    Join Date
    Feb 2007
    Location
    California USA
    Posts
    4,119
    Thanks Thanks Given 
    5
    Thanks Thanks Received 
    57
    Thanked in
    51 Posts

    Re: H Type Carburetors BN2 M version Leaking Fuel At Jet Bearing Area

    I'm (just guessing) that pre-oiling cork gaskets may not be appropriate in this case. My dad rebuilt a pair of M carbs, and I'm pretty sure he didn't pre-oil anything, and I get a little bit of seepage from the bottom of the carbs but not enough to worry about. The gaskets should swell a little when gas gets to them. Soaking/pre-oiling is correct for 'Oilite-type' bronze bushings, and I've never heard of anybody having any luck soaking cork in oil (doesn't mean it hasn't happened, of course)

  13. #13
    Jedi Hopeful
    Join Date
    May 2013
    Location
    Australia
    Posts
    124
    Thanks Thanks Given 
    1
    Thanks Thanks Received 
    2
    Thanked in
    2 Posts

    Re: H Type Carburetors BN2 M version Leaking Fuel At Jet Bearing Area

    I have found that the neoprene cork type don't really need soaking but it was apparently the thing to do with the originals.

    Danny
    Attached Images Attached Images

  14. #14
    Yoda
    Join Date
    Feb 2007
    Location
    California USA
    Posts
    4,119
    Thanks Thanks Given 
    5
    Thanks Thanks Received 
    57
    Thanked in
    51 Posts

    Re: H Type Carburetors BN2 M version Leaking Fuel At Jet Bearing Area

    Can't argue with the experts.

  15. #15
    Jedi Hopeful
    Join Date
    May 2013
    Location
    Australia
    Posts
    124
    Thanks Thanks Given 
    1
    Thanks Thanks Received 
    2
    Thanked in
    2 Posts

    Re: H Type Carburetors BN2 M version Leaking Fuel At Jet Bearing Area

    Can't argue with the experts.
    Absolutely! We know that BMC/BL never made any mistakes.

    Danny

Bookmarks

Posting Permissions

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