Marvel "V" Carburator Question

30essex
30essex Senior Contributor
edited November -1 in HUDSON
I have a couple of questions concerning the Marvel "V" carburator on my 1930 Essex.

The first question is about the accelerator pump. When I pull it out, only the thin shaft comes out (see attached picture). There is a brass object stuck in the bottom of the well. I take it that this is supposed to be attached to the shaft. How do I get it out and how should it be attached?

The second question is about the float level. When I brake to a stop, the engine often stops. I think this is caused by the gas level being to high in the bowl and gas overflowing. What is the proper level for the float and how do you adjust it? Thanks.

Comments

  • Geoff
    Geoff Senior Contributor
    This part should have a washer on the bottom, and a heavy round brass plug which idles on the shaft. The action of the pump is that when you depress the pedal, the shaft and washer are pushed down in the cylinder of the carburettor, and displace the fuel into the jet. The heavy plug is idling on the shaft, hence it will only fall under it's own weight as the shaft is lowered. It then falls under it's own weight, displacing more fuel through the jet, and prolonging the discharge. To set the float level, you need to set the carburettor up on the bench, with a gallon tin of fuel connected to it, with a tap so you can turn it on and off. Remove the float bowl cover, and with a depth gauge, measure the distance from the top of the bowl to the top of the low-speed jet, and adjust the float lever so that the fuel comes up to 1/8" below this level. You will have to be very careful bending the lever that you don't damage the cork float. You have to remove the float to adjust it. Good luck,

    Geoff.
  • 30essex
    30essex Senior Contributor
    Thanks Geoff. However the brass plug is stuck solid in the bottom of the cylinder. I've soaked it in penetrating fluid but there seems to be no way to get it out. Anyone have any ideas as to what I can do to loosen it?
  • Geoff
    Geoff Senior Contributor
    Try an "Eazi-out" in the hole in the middle of the plug, this should wind itself down and wedge tight, which should loosen it and allow you to pull it out.

    Geoff.
  • 30essex
    30essex Senior Contributor
    Geoff, I tried that. There is a sleeve inside that turns freely so you can't get anything to turn into it. Any other ideas? Thanks.

    Arend
  • 30essex
    30essex Senior Contributor
    Well, I finally got the thing out. I broke out the centre sleeve and tapped the hole with a 3/8 tap. I then threaded in a 3/8 bolt with a nut and washer and pulled it out by turning down the nut. I'm relieved I didn't break the carburator body since one like it went for about $900 on e-bay a couple of weeks ago.

    I had to put in a new sleeve to make the hole fit the shaft and solder on the washer. The carburator should be ready for assembly tomorrow.
  • Geoff
    Geoff Senior Contributor
    Great, you now have it assembled like it should be. There is one other thing to check for. In the small chamber under the "Summer / winter" needle - there should be a flat disc sitting over the orifice. When the needle is in the winter position, it holds the disc down over the orifice, which blocks it off, and the accelerator pump then comes into play, as the fuel has to go through the jets. when in the summer position the disc will float, and the fuel will come back into the float bowl with only a small amount going through the jet. This disc often falls out when people pull the carburettor apart. if it is missing you can cut a new one out of .010 shim brass.

    Geoff.
  • 30essex
    30essex Senior Contributor
    Thanks, Geoff. The disk is missing and I'll make a new one.
  • 30essex
    30essex Senior Contributor
    I made a 3/8 in. disk and put it in from the bottom. I hope that is correct.
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