Results 1 to 20 of 20

Thread: Problem with 259 Engine

  1. #1
    President Member
    Join Date
    Jul 2008
    Location
    Central Florida
    Posts
    599

    Problem with 259 Engine

    Engine will crank up, run for a few seconds and quit. Pump the accelerator a couple times, will start again and run for a few seconds. Start it again (without pumping the accelerator and engine will run for a few seconds and quit. Pop the horn off and bowl is full of fuel. Hold the choke closed and engine will continue to run. No problems with fuel to carb, both mechanical pump and electric pump produces 5-7 lbs pressure. Everything in WCFB carb reworked, setup correctly (as per shop manual), timing spot on, ign. spot on. New pistons, rings (+.030), compression a bit lower then I like at 130psi, but it hasn't been run more then a couple minutes??? I'll recheck compression tomorrow, but should crank and run with 130psi. I'll be checking vaccum tomorrow, but appears to be plenty. Any ideas??? What am I missing???
    Bo

  2. #2
    President Member Jerry Forrester's Avatar
    Join Date
    Aug 2007
    Location
    Douglasville, Georgia, USA.
    Posts
    3,310
    Quote Originally Posted by Bo Markham View Post
    Engine will crank up, run for a few seconds and quit. Pump the accelerator a couple times, will start again and run for a few seconds. Start it again (without pumping the accelerator and engine will run for a few seconds and quit. Pop the horn off and bowl is full of fuel. Hold the choke closed and engine will continue to run. No problems with fuel to carb, both mechanical pump and electric pump produces 5-7 lbs pressure. Everything in WCFB carb reworked, setup correctly (as per shop manual), timing spot on, ign. spot on. New pistons, rings (+.030), compression a bit lower then I like at 130psi, but it hasn't been run more then a couple minutes??? I'll recheck compression tomorrow, but should crank and run with 130psi. I'll be checking vaccum tomorrow, but appears to be plenty. Any ideas??? What am I missing???
    Sounds like you have a severe vacuum leak. Probably the carb./manifold gasket.
    That's where mine was. Same symptoms.
    Jerry Forrester
    Forrester's Chrome
    Douglasville, Georgia

    See all of Buttercup's pictures at https://imgur.com/a/tBjGzTk


  3. #3
    President Member
    Join Date
    Jul 2008
    Location
    Central Florida
    Posts
    599
    Quote Originally Posted by Jerry Forrester View Post
    Sounds like you have a severe vacuum leak. Probably the carb./manifold gasket.
    That's where mine was. Same symptoms.
    Jerry,

    Tapped into the throttle body at back of carburetor. Holding choke closed, engine running, 21 HG vaccum, constant at high idle. Let the choke off, engine dies??? I'm beginning to think something internal to front half of carburetor???
    Bo

  4. #4
    Silver Hawk Member
    Join Date
    Dec 2006
    Location
    Sacramento, CA, USA.
    Posts
    5,124
    Ditto to above comments. If the engine is getting enough air to stay running while the choke is closed, then its getting the air from somewhere else. Before you start pulling the heads off, check all your other areas of vacuum. PCV, carb to manifold gasket, vacuum lines to distributor, vacuum line to brake booster. Check every avenue of whatever attaches to the intake manifold to see if there are loose hoses, cracked hoses, missing hoses. Last resort.... pull the intake and see what the gasket looks like.
    As an aside.. I've re-used intake gaskets for these kinds of checks by spraying the copper gasket sealer over a wire brushed, used steel gasket with great success.
    I've also cut my own gaskets with the thick gasket paper for a quick check of sealing. These will eventually blow out at the heat riser cross over, due to the heat. 5 minutes with a ball peen hammer will cut a gasket in short order, as sometimes they are not readily available locally. Why wait?
    Good luck with the search. Here's hoping for an easy fix, eh?
    sals54

  5. #5
    President Member
    Join Date
    Jul 2008
    Location
    Central Florida
    Posts
    599
    Quote Originally Posted by sals54 View Post
    Ditto to above comments. If the engine is getting enough air to stay running while the choke is closed, then its getting the air from somewhere else. Before you start pulling the heads off, check all your other areas of vacuum. PCV, carb to manifold gasket, vacuum lines to distributor, vacuum line to brake booster. Check every avenue of whatever attaches to the intake manifold to see if there are loose hoses, cracked hoses, missing hoses. Last resort.... pull the intake and see what the gasket looks like.
    As an aside.. I've re-used intake gaskets for these kinds of checks by spraying the copper gasket sealer over a wire brushed, used steel gasket with great success.
    I've also cut my own gaskets with the thick gasket paper for a quick check of sealing. These will eventually blow out at the heat riser cross over, due to the heat. 5 minutes with a ball peen hammer will cut a gasket in short order, as sometimes they are not readily available locally. Why wait?
    Good luck with the search. Here's hoping for an easy fix, eh?
    Forgot to mention, engine is on test stand. 60 model 259, so no PCV. Only thing Vaccum operated is the modifier on the distributor. Installed a thicker carburetor to intake gasket. I've checked the steel line going to the modifier, not leaks. No leak under the carburetor. I've not been able to check the intake, that't next??? I think I'll try the copper coating on the intake if it is the problem.

    Thanks
    Bo

  6. #6
    Silver Hawk Member
    Join Date
    Dec 2004
    Location
    Trochu, Alberta , Canada.
    Posts
    5,406
    I will chime in to say that 21" of vacuum with the choke closed is meaningless. Vacuum reading at idle, choke open, will tell the story.
    Gord Richmond, within Weasel range of the Alberta Badlands

  7. #7
    President Member
    Join Date
    Apr 2005
    Location
    mass
    Posts
    3,741
    I'm unsure as to "WCFB re-worked ???

  8. #8
    President Member
    Join Date
    Jul 2008
    Location
    Central Florida
    Posts
    599
    Quote Originally Posted by gordr View Post
    I will chime in to say that 21" of vacuum with the choke closed is meaningless. Vacuum reading at idle, choke open, will tell the story.
    Well gordr, if I could get the engine to run at idle without the choke closed, I probably wouldn't have a problem. Since the engine starts, runs for a few seconds then quits, what's a fella to do??? I've found no vaccum leaks either between the carburetor and intake, intake and block, or in the steel line to the modifier??? There are not other vaccum connects, except the rear of the throttle body and the plug isn't leaking.
    Bo

  9. #9
    President Member
    Join Date
    Jul 2008
    Location
    Central Florida
    Posts
    599
    In this case, it means a working WCFB that got a good cleaning/dipping in carburetor cleaner vat, a new kit put in it and put on the engine. I've got it apart on the bench now, checking to ensure I made all the adjustments correctly.
    Bo

  10. #10
    Silver Hawk Member bezhawk's Avatar
    Join Date
    Jan 2008
    Location
    here, sometimes somewhere else
    Posts
    5,697
    Could have been the metering rod vacuum piston sticking, or the metering rods off the mechanical lifting tab, located on the shaft under the top small cover. Also a bent float rubbing on the sides won't meter fuel properly. Height as well as side to side alignment is critical on WCFBs.
    Bez Auto Alchemy
    573-318-8948
    http://bezautoalchemy.com


    "Don't believe every internet quote" Abe Lincoln

  11. #11
    President Member bensherb's Avatar
    Join Date
    Jun 2015
    Location
    Tracy / Goleta Ca.
    Posts
    907
    You also might want to check that your vacuum Ignition modifier (I love this term, it's actually a more appropriate description) will hold vacuum. Sometimes the diaphragm will crack and create a vacuum leak.

  12. #12
    Silver Hawk Member
    Join Date
    Dec 2004
    Location
    Trochu, Alberta , Canada.
    Posts
    5,406
    Quote Originally Posted by Bo Markham View Post
    Well gordr, if I could get the engine to run at idle without the choke closed, I probably wouldn't have a problem. Since the engine starts, runs for a few seconds then quits, what's a fella to do??? I've found no vaccum leaks either between the carburetor and intake, intake and block, or in the steel line to the modifier??? There are not other vaccum connects, except the rear of the throttle body and the plug isn't leaking.
    Well, about all you can do is to get it running on choke, watch the vacuum gauge, and then open the choke. See what the gauge does. Watch the momentary reading as soon as the choke is opened; it should drop from 21" to somewhere between 12" and 18", for a rough guess. If it plateaus at some level, and then drops again steadily as the engine dies, then that's going to be close to your true vacuum reading. I doubt the distributor vacuum line is the source of your vacuum leak (if one exists at all), because the line is simply too small to matter that much.
    Gord Richmond, within Weasel range of the Alberta Badlands

  13. #13
    President Member
    Join Date
    Jan 2013
    Location
    british columbia
    Posts
    1,157
    Check that you metering rods are not bent, they are tricky to reinstall, the top cover has to be removed to set them in correctly then the cover replaced. When I firstly re and reed my afb I bent one of the metering rods and didn't notice it. The next thing I would check is the idle jet and confirm it is clear. I had a jet on a small motorcycle that had a small piece of machining stuck in it. Looking through the jet at the sun you could see it but it would not come out. The jet was replaced with a new one and it was like magic. There is/was small jet cleaning tools I, have a set they are very old school but work well. They are like very small round files but made for carburetor jets. Even though it is assembled correctly, each component must be inspected for condition, something in the fuel delivery system is obstructed.

  14. #14
    President Member thunderations's Avatar
    Join Date
    Nov 2012
    Location
    Phoenix, AZ
    Posts
    1,551
    Disconnect and plug the vacuum line to the distributor. See if the engine runs OK. If so, the problem is the vacuum advance in the distributor.
    1966 Daytona (The First One)
    1950 Champion Convertible
    1950 Champion 4Dr
    1955 President 2 Dr Hardtop
    1957 Thunderbird

  15. #15
    President Member
    Join Date
    Jan 2013
    Location
    british columbia
    Posts
    1,157
    I don't think the small amount of vacuum from the modifier would make any difference, it is disconnected on a regular basis to adjust and check timing and the engines run fine with it or with out it. You will get a difference pitch in the engine but it will not die if you open and close the vacuum to the carburetor.

  16. #16
    President Member
    Join Date
    Jul 2008
    Location
    Central Florida
    Posts
    599
    Quote Originally Posted by Jerry Forrester View Post
    Sounds like you have a severe vacuum leak. Probably the carb./manifold gasket.
    That's where mine was. Same symptoms.
    Update. Massive vaccum leak underneath intake passanger side rear ports. Stuck an adaptor with a good 2bbl. on it and it ran well enough to find this problem. Had to do so work on the surface of the intake, but it corrected that problem. Also, used copper sealer on new intake gaskets. No more vaccum problem. Put the rebuilt WCFB back on and the engine cranked, ran for a few seconds and quit?????? Arghgggggggggggggg!!!

    I'm now convinced that it is an internal problem with the carburetor, some where in the front (low speed) section. Tomorrow is another day........
    Bo

  17. #17
    Golden Hawk Member StudeRich's Avatar
    Join Date
    Dec 2005
    Location
    Ferndale, WA, USA.
    Posts
    28,384
    When you get a chance to open up the WCFB, check that the Primary Jets are not crossed with the Secondary Jets.
    StudeRich
    Second Generation Stude Driver,
    Proud '54 Starliner Owner




  18. #18
    Golden Hawk Member jclary's Avatar
    Join Date
    Dec 2008
    Location
    Greer, sc, USA.
    Posts
    10,267
    Well, it looks like you found one of at least two problems. If that vacuum leak is truly fixed, then you are more likely to have success with the carburetor since it can now be the main area of your focus. Good luck.
    John Clary
    Greer, SC
    [IMG][/IMG]
    SDC member since 1975

  19. #19
    President Member
    Join Date
    Jul 2008
    Location
    Central Florida
    Posts
    599
    Problem finally solved. PO had at some point changed out the metering rods and primary jets, replacing the OEM with some very large ones. One of the problems with this was that the primary and secondary jets were virtually the same size and I didn't notice this, so I put the slightly smaller ones back in the primary position. This created a really lean unadjustable configuration for the carburetor. Reversed these and the car ran fine with air/fuel adjustment, except that now it would spit back through the front half of the carburetor under aggressive throttle advancement. Apparently, according to my good friend Dave Thibeault, this metering rod/primary jet conversion would have worked on a high mileage engine (which it did), but would not on a freshly rebuilt engine. He was right. Replaced these with OEM std. metering rods and jets and whallaaaaaa!!! Carburetor adjusted out nicely and car runs like a new one.

    Dave's a great guy, and we thank him for the assistance and the knowledge he shared with us about this carburetor problem.
    Bo

  20. #20
    President Member (S)'s Avatar
    Join Date
    Aug 2010
    Location
    Ferndale, Washington
    Posts
    1,854
    Good call Dad!

Posting Permissions

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