Opinions about setting the float level in the WA-1 carb for a single carb stepdown.

Rob Fayette
Rob Fayette Expert Adviser
in HUDSON
I have  heard comments over the years about changing the float level in step down carburetors.  There were reasons such as changing it to account for the different density of ethanol or changing it to prevent the engine from cutting out when going around corners.  I tried searching for info on this forum but I didn't find anything.  It seems to me that if you set the float to high that that would cause an over rich mixture and result in poor gas mileage.  Is that correct?  I'm hoping this thread will cause a thorough discussion on float levels.  Thanks

Comments

  • bob ward
    bob ward Senior Contributor
    Modern petrol is lighter than 1950's petrol. How much lighter I don't know but the better carby guys (and aren't they getting thin on the ground) will adjust (bend the arm of) the float so you still get the correct fuel level in the bowl.

    How the carby man knows how much to tweak the float arm I don't know, its one of those things makes a good carby guy a good carby guy.


  • Hudson Grandpa
    Hudson Grandpa Expert Adviser

    Last year I bought a used carb from Al in Tucson to learn.  Did I eveer learn.  Daytona kit, and then followed the Hudson Manual.  I had the float on the money at the front end, but over the money at the rear.  Put it on the car, and car was hard to start, and ran very rough at cold idle.  So I took carb off, and very diligently measured the float front to back.  Had to bend the arm. Measuerd, measuerd, and again. Paid close attention to the auto choke when replacing the carb.  Ever since then the car starts so easy I can't stand it, and when cold goes on the high idle right off.  If all the kit parts are installed correctly and you have problems, then it's the float level. That little round screen inside the carb where the fuel enters from pump,needs to be taken out, checked and cleaned every now and then. When you take that off also take off the top of the carb next to the mouth of the carb and squirt some WD-40 in there.  Thats what squirts the gas into the barrel. Needs to operate freely.  Corn gas builds up crap in that area.  I add STP fuel injector & carbeurator treatment to the gas, and that seems to help lubricate the parts in the carb.

    Happy carbuerating...

  • Geoff
    Geoff Senior Contributor
    It's very much "hit and miss".  As Bob says, unleaded gas today is different form what they had back in the fifties, but I don't know the difference between straight mineral unleaded petrol and  ethanol blends.  The problem is the modern fuels are lighter viscosity (thinner) and also are lower specific gravity  (weigh less). Generally speaking, the straight  mechanical adjustment as in  the workshop manual does not necessarily work, as it is just a line in the sand so to speak.   If your car runs too rich, then the float level is probably too high, and if it  hesitates  and coughs, it is most likely too low.  Rule of thumb with the unleaded petrol we have here in New Zealand is to drop the float adjustment by 1/8" .  Works for me.
    Geoff 
  • Rob Fayette
    Rob Fayette Expert Adviser
    Thanks for the ideas everyone.   I think I will experiment with the float level and try to compare it with how rich the engine seems and how it varies the fuel economy.

    Rob
  • Geoff
    Geoff Senior Contributor
    For accuracy you cannot beat an exhaust gas analyser, but I don;t know how good they work on  unleaded ethanol gasoline. 
  • bob ward
    bob ward Senior Contributor
    HG, Geoff, Ken, what is your technique for measuring how much you have dropped the fuel level in the float bowl? 
    Where and how do you measure the before and after?
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