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Technical 1950 Mercury Flathead Help

Discussion in 'Traditional Customs' started by Christopher Falanga, Aug 16, 2019 at 6:03 AM.

  1. Need some help with a 1950 Mercury I just purchased. The car has its original 255ci flathead V8 and is still a 6v car. The guy I got it from claims it was was a running driving car. Got it home and he had changed the plugs, wires condensor points, installed an electric fuel pump all because it wouldnt start one day. He got it to start which is the condition I got it in. After getting it home and lowering it, took it for a road test and discovered it will not go over 20mph, even with your foot all the way to the floor. I have checked timing, points gap, and plug gap and they are all good. disconnected electric fuel pump and reconnected mechanical one. I am getting gas spark and air and the car will idle just fine, but like i stated 20mph is as fast as she will go. Has the original carb as well, and noticed when you give it any gas the choke closes on it, not all the way but enough that i think that maybe my issue but not 100% sure. Any help on this issue would be greatly appreciated.

    Thanks,
    Chris
     
  2. Petejoe
    Joined: Nov 27, 2002
    Posts: 9,944

    Petejoe
    ALLIANCE MEMBER
    from Zoar, Ohio

    Hello Chris and welcome to the H.A.M.B.
    When your choke partially closes when you increase rpm, it is flooding the engine with fuel.
    Not familiar with a mercury carburetor. Someone here with this knowledge should be able to get you straightened out.

    Here’s some info on the teapot carb.
    https://www.fordbarn.com/forum/showthread.php?t=7657

    Let’s see some pictures of the car.
     
    Last edited: Aug 16, 2019 at 6:21 AM
  3. Boneyard51
    Joined: Dec 10, 2017
    Posts: 2,078

    Boneyard51
    Member

    Sounds like you have found your problem. Your choke linkage should be checked. Also check your linkage to make sure you are opening the throttle plates all the way.





    Bones
     
    Last edited: Aug 19, 2019 at 4:44 PM
    Chappy444 and ClayMart like this.
  4. J'st Wandering
    Joined: Jan 28, 2004
    Posts: 1,585

    J'st Wandering
    Member

    I am sure this is not the problem but just something to keep in mind. I had a pickup that had the muffler plugged with a mouse nest and it did the same thing you describe.
     
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  5. Like Boneyard said, it sounds like you are on the right track. There should be some way to wire the choke in the fully open position at normal engine operating temperature for diagnostic purposes. It may just make the engine a little harder to start cold. Is it an automatic or manual choke?

    It wouldn't hurt to post a couple of underhood pictures here showing the engine from a few different angles.

    J'st Wandering makes a good point about an exhaust restriction. This condition should show up while doing an engine manifold vacuum test. A vacuum gauge can also help locate other tune-up and engine condition issues.


    https://dannysengineportal.com/how-to-do-a-vacuum-test/
    :D
     
    lothiandon1940 likes this.
  6. Automatic Choke
     
  7. Chris, welcome to the H.A.M.B. There are so many different possibilities that can cause your issue that for me a 2 finger hunt-n-pecker I can't help ya out. Go find some Old Guy like me that would like to bend over the fender with ya and fix it for ya. Ya, I'm a Mechanic guy neighbor like that.
     
    lothiandon1940 likes this.
  8. ...................This. If you are willing to put a location in your profile, there might even be someone nearby that could share some experience.
     
  9. town sedan
    Joined: Aug 18, 2011
    Posts: 1,020

    town sedan
    ALLIANCE MEMBER

    Carb may be your problem, but let's not for get about the much loved Load-O-Matic ignition system. If you keep the original distributor you must have a compatible carburetor. If not problems...,
    -Dave
     
    ClayMart likes this.
  10. So what we really know about your issue is that the previous owner had an issue that wasn't diagnosed properly and just changed a bunch of stuff that may or may not have had anything to do with why it wouldn't start. Hell, you could simply have a plugged up exhaust pipe not letting it get rid of what your stuffing down it's intake. Tell us this please, just exactly what does it do when it try's to run? Have you manually made the choke stay open so it has a chance of not being so rich it can't accelerate (meaning R.P.M.)?
     
  11. carbking
    Joined: Dec 20, 2008
    Posts: 2,477

    carbking
    Member

    Get the choke working first.

    You may have other issues, but you KNOW the choke is not working.

    From my website articles:

    Operation – integral hot air chokes

    The integral choke, like the divorced choke, closes due to a coiled bimetallic strip that rotates with temperature change. The coil is located inside the integral choke housing. Also inside the choke housing is a vacuum piston assembly. An internal vacuum source enters the choke housing behind the vacuum piston, and escapes by the choke piston to cause a negative pressure (vacuum) on the entire integral choke housing. As the housing is connected to the hot air choke tube, this negative pressure pulls air heated by the exhaust through the heat tube. This hot air causes the tension of the coil to relax, allowing the vacuum piston (this may be thought of as an internal choke pulloff) to open the choke plate.

    Adjustment – all except electric chokes and the 1937-38 Delco unit

    All chokes other than the above may be adjusted as follows: pick a time with the ambient temperature is between 65 and 70 degrees F. (68 degrees F. is the perfect temperature), and adjust the choke such that the choke plate on a cold engine just TOUCHES closed, with zero tension. The choke coil will then compensate for other temperatures.

    Jon.
     
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  12. s55mercury66
    Joined: Jul 6, 2009
    Posts: 3,450

    s55mercury66
    Member
    from SW Wyoming

    A quick tip, you can check the exhaust by sticking your in front of it, that will tell you if it is substantially plugged. Do fix the choke first.
     
  13. Atwater Mike
    Joined: May 31, 2002
    Posts: 9,499

    Atwater Mike
    ALLIANCE MEMBER

    "By sticking your...What?.. in front of it", Dusty? I'm guessin'...
     
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  14. s55mercury66
    Joined: Jul 6, 2009
    Posts: 3,450

    s55mercury66
    Member
    from SW Wyoming

    Oh shit! I got sidetracked there for a minute. Yes Mike, I typically use my hand for this check.
     
  15. BJR
    Joined: Mar 11, 2005
    Posts: 5,541

    BJR
    Member

    Had me worried for a moment there.:eek:
     
  16. R A Wrench
    Joined: Feb 4, 2007
    Posts: 417

    R A Wrench
    Member
    from Denver, Co

    the coil could be dying, weak spark & only letting it barely run.
     
  17. v8flat44
    Joined: Nov 13, 2017
    Posts: 118

    v8flat44

    Go to the Ford Barn....lots of sharp flathead guys. I love the H A M B, but sometimes The Barn is where to go.
     
  18. yes ive tied the choke open, when you go to accelerate it will go along pretty good til about 20 mph then it just wont go anymore, especially up hill. upon initial start up it does blow a large amount of water and carbon in a wet black mess.
     
  19. It is also currently running extremely hot, anytime i make adjustments or try stuff that others have recommended and i drive it around the block 4-5 times when i pull it back in the driveway the temp gauge is all the way on the H
     
  20. Petejoe
    Joined: Nov 27, 2002
    Posts: 9,944

    Petejoe
    ALLIANCE MEMBER
    from Zoar, Ohio

    It’s time for you to do a compression check.
    You are now in a position where you may have a blown head gasket (hopefully) easy fix or a cracked block. Not so easy.
     

  21. did one, compression as follows
    1 - 95
    2 - 100
    3 - 97
    4 - 95
    5 - 100
    6 - 107
    7 - 75
    8 - 110
     
  22. Petejoe
    Joined: Nov 27, 2002
    Posts: 9,944

    Petejoe
    ALLIANCE MEMBER
    from Zoar, Ohio

    Your obviously introducing moisture into your cylinders somewhere. Before pulling any heads off, Run a cylinder pressure test now. Should be easy to find where this leak is.
     
  23. xix32
    Joined: Jun 12, 2008
    Posts: 436

    xix32
    Member

    Put a timing light on it and see if it goes retarded, while the rpm increases. Then suspect that distributor with that
    "Load-A-Matic" vacuum advance system. You might try the "FordBarn" for advise about them.
     
    Last edited: Aug 19, 2019 at 11:29 AM
  24. xix32
    Joined: Jun 12, 2008
    Posts: 436

    xix32
    Member

    A typical cause of flatheads running hot is retarded timing, because the exhaust gases are still burning when the exhaust valve opens, then the hot ( still burning) gases have to make the long trip from the valves along side the cylinders and water jackets before they exit the block.
    Again, I would suspect your timing.
     
  25. sunbeam
    Joined: Oct 22, 2010
    Posts: 4,047

    sunbeam
    Member

    Hook up a vacuum gauge and check
     
  26. V8 Bob
    Joined: Feb 6, 2007
    Posts: 2,417

    V8 Bob
    ALLIANCE MEMBER

    The normal temp gauge sending unit is on the right (passenger) head and provides gradual readings. This current passes through a 212* F switch on the left head, so one gauge can monitor both sides of the flathead's cooling system. You may have one or two defective T-stats, sending unit or switch.
     

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