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Technical 1940 Mercury coupe flathead HELP

Discussion in 'The Hokey Ass Message Board' started by Blake84, Dec 29, 2018.

  1. Blake84
    Joined: Feb 4, 2012
    Posts: 738


    I just bought a 1940 Mercury that seems to have an early Ford flathead with the crab style distributor. I just took it for a cruise and I had 2 issues I was hoping someone can help me with.

    ISSUE 1

    When I give it alot of gas and I'm in 3rd gear it starts to bog out and feels like its starving for fuel and occasionally stalls. Once the engine shuts off it starts back up no problem so I am getting the feeling its starving for fuel. How do I adjust this on a single barrel carb? It also bogs out when under alot of throttle in all gears but I usually shift before it stalls.

    Also, once I really give it gas and it stalls it will no longer idle nicely it starts to feel like it's going to cut out and then eventually does cut out. When I first start the car it idles totally fine. I'm just wondering why it will idle fine and then after I drive it for a bit and give it some gas it no longer wants to idle?

    ISSUE 2

    3rd gear occasionally pops out of gear on the transmission. Any idea how to adjust this?

    Side note. How exactly do you use the Over drive on the trans? It's a little pull cable and I'm just curious how to engage it and disengage it? Does it need to be disengaged once engaged or does it automatically disengage with speed?

    Thanks in advance! I cant wait to take it for a spin but I want it to run nice :)

    Attached Files:

    hotrodharry2 and chryslerfan55 like this.
  2. Mac VP
    Joined: May 13, 2014
    Posts: 364

    Mac VP

    Sounds like you’re going to be doing a lot of learning about your car...... there will be plenty of suggestions coming forth here. Try to be systematic about your diagnosis approach.

    First, I’d suggest temporarily trying to run the car without that air looks like the cheap kind that is highly restrictive. If your engine runs and pulls better, replace the filter element or get a stock type on it.

    Look for a fuel filter somewhere.....try replacing that in case it’s clogged. Also, make sure the gas tank filler cap is vented. There could be a fuel supply issue related to the fuel pump. Do a suction test and/or an output test on the pump.

    The distributor could be out of time. Or have dirty or worn points. A common ignition problem with the original type coil is a failure under heat, doing what you’ve described in running rough and then failing until it cools down. A correct rebuilt coil can fix that.

    As for the transmission, it sounds like someone has changed out the stock original transmission to something with overdrive since Ford didn’t offer that in their Ford or Mercury lines back then. Try to ID which transmission is in there now and perhaps we can help with accurate advice.
    flatford39 and Petejoe like this.
  3. Petejoe
    Joined: Nov 27, 2002
    Posts: 11,077

    from Zoar, Ohio

  4. BJR
    Joined: Mar 11, 2005
    Posts: 7,150


    It could have a 2 speed rear end in it, instead of an overdrive transmission.
    flatford39 likes this.

  5. alchemy
    Joined: Sep 27, 2002
    Posts: 17,268


    A couple things right off the bat. The distributor is not a crab style, it is a 1941 and previous, commonly known as a diver's helmet style. We would need a good close up pic to determine the year.

    The car also has post war heads on it, so that could mean it just has post war heads, or the whole engine could be post war. Check the top of the bellhousing cast into the block for any big lettering. Look down the backside of the engine in front of the firewall. This would give a clue as to the year generally the block was made.

    And, it has a bit of funky plumbing made out of pipe fittings screwed into the front of the carburetor base that is not stock. See if you can tell where this stuff leads and let us know.

    As for the transmission, there is no way to adjust that problem if it is internal. But, you could check and see if your linkage has nice tight joints. If it needs linkage parts I would go to Mac Van Pelts website and buy them there. He is the master of old Ford transmissions.
    flatford39 likes this.

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