cjmarzoli

Keeping gas in a Marvel updraft carburetor when parked. Where does it go?

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Bloo- a five gas analyzer is a must.........as is a chassis dyne. After twenty five years of tuning pre war carbs for E-10, we can usually get very close to where we want to be based on engine type, displacement, and a few other factors all before we begin testing with the equipment. I set up ALL my car on the rich side. Too many people run cars too hard and melt valves and burn pistons if you run it on the lean side. Most....95% .."....never drive more than token mileage today on pre war stuff. 

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Benefits of AACA Membership.

My 1931 has operated for 89 years on its original mechanical fuel pump, which I rebuilt last year and which operates perfectly, so why would I want to add an electric pump now?  For starters, it's not correct, and requires adding new wiring, lines, brackets, regulators, etc to my car.  That's also why I don't install electronic ignition or radial tires on it.  It adds needless electronic complication, is another component to fail, and potentially leave me stranded.  Anything that can be accomplished mechanically vs electronically is a good thing in my book.  As others have pointed out, it is also a potential fire hazard if improperly installed and used, and not turned off or on at the right time.  Who wants to deal with that?  Its easier just to prime the carb before starting or just crank it a few more times.  I believe in keeping old cars as close to factory stock as possible.  

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Posted (edited)
11 hours ago, cjmarzoli said:

  I believe in keeping old cars as close to factory stock as possible.  


Insight that is bordering on genius................It’s how I service and repair all my cars. 🤔

Edited by edinmass (see edit history)

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On 5/18/2020 at 10:56 PM, cjmarzoli said:

Did gas in the 1930's not evaporate?  

The gasoline formulas were different than today. 

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14 hours ago, cjmarzoli said:

My 1931 has operated for 89 years on its original mechanical fuel pump, which I rebuilt last year and which operates perfectly, so why would I want to add an electric pump now?  For starters, it's not correct, and requires adding new wiring, lines, brackets, regulators, etc to my car.  That's also why I don't install electronic ignition or radial tires on it.  It adds needless electronic complication, is another component to fail, and potentially leave me stranded.  Anything that can be accomplished mechanically vs electronically is a good thing in my book.  As others have pointed out, it is also a potential fire hazard if improperly installed and used, and not turned off or on at the right time.  Who wants to deal with that?  Its easier just to prime the carb before starting or just crank it a few more times.  I believe in keeping old cars as close to factory stock as possible.  

I tend to agree here.  

 

Where I disagree though is that the gasoline formulas are different, so I have had the need to add an electric pump for priming purposes (and that is really a touchy "safety" issue with cars with carbs that cannot hold back pressure, vacuum tanks, and ....).  I can generally get original carbs and vacuum tanks to work - problem is pulling fuel via heat sink issues.  And, I can get a car to run fine with no modification, but whole different story of a leisurely tour a couple neighborhoods over verses I have to drive someplace for two hours to get to the tour and then drive for hours on end matched to then getting home. 

 

And I have had to relocate fuel lines and eliminate pre-heating features on several cars, plus such as insulation wrapping fuel lines and wrapping exhaust. 

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Down here in Aussie  we call it petrol. I don’t know what is in USA gasoline but from my experience when visiting it is much the same except here ethanol is optional;E10. We have 91 and ‘premium’ 98 octane and variants. A while back I was given the task of supplying heat exchanger/chiller for the local fuel refinery. It’s function was to keep the fuel in the bunker below 24’c (@75’F). This was to prevent  pentane from boiling out of the gasoline. This is added to make the gasoline ignite. Hence one reason why modern cars have sealed fuel systems and why your small domestic engines won’t start if you leave the gasoline in there more than a month, particularly in warm weather. The pentane boils off.  After about a year you can pour the fuel on the ground and try and light it with a match and the match drowns!.. Vaporising of fuel is now the big problem with older cars and the cooler you can keep the gasoline the better.  There is other ‘stuff’  added as well. Do you notice in bottom of the float bowl and on the jets a light brown powder stuck to it.This tends to make the needle and float stick and cause flooding. When stuck on the mid and main jets will cause lean out.  Carby cleaners or other solvents won’t remove it. The only way is to clean it is mechanically with a soft wooden tapered stick,gently applied. Definitely have a fire extinguisher handy at all times located at the rear of the car. CarbKings’ idea of a ‘push on’ only button to operate the electric pump I do like. 

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Ingredients like heptane, alcohol, oxygenation agents, injector cleaners, smog reduction agents, are just a few things. Volume, specific gravity, boiling point, suspension products.........hell even the molecular structure of the carbon binding from a chain to a ring are all different now..........Heat and energy content are also lower. Fuel is made to be in a CLOSED system, without the ability to vent to the air. When modern fuel is exposed to oxygen it immediately begins to degrade. Pour a few ounces of “gas” on a cement pad and let it evaporate........it leaves a stain. Get it on your skin, and it burns like hell. And obviously it smells much different. There are lots of tricks to make your car run better, eliminate vapor lock, and start easier hot or cold.......but it all takes time and money. 

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One other possible solution is you could build up a AC mechanical pump with a hand prime lever. There is one on my Buick but I don't need to use it. They were common on marine engines like the Chris Crafts K series, AC pump number 4294. Then and Now Auto Parts offered to build another one up for me so they can probably still do one.

 

Dave

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Here is a picture but it may not help much. The u shaped wire is the primer lever. I checked the catalogs and it was used on many marine engines but probably has to be one that uses  a pump with a top and bottom cover. The only problem I had with my boat was when the engine happened to stop with the pump arm all the way in but all you had to do was bump the starter.

 

Dave

fuel pump primer.jpg

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I have not had any carburetor problems since I switched to no alcohol fuel.  My 1933 sat all last winter, it did not turn over more than 10 seconds and was running this spring, full choke till start.  I don't even bother with fuel stabilizers any more.  I run BB1 updrafts on all my Grahams.  I have more problems with my 1980 1 ton dully, if my son puts in the cheap, alcohol fuel it evaporates as soon as the truck is shut off, it cranks over longer than any of my pre-war cars to fill the float bowl, it runs a 500 Edelbrock with aluminum intake.  We went years in Minnesota not being able to purchase anything but alcohol fuel, I will use the non-alcohol as long as it is available for all my old cars, well in anything that is not a sealed fuel system. 

 

I am not a fan of the electric fuel pumps, removed them from all my cars that had them, over 10 years ago.  My Grandfather drove his Graham with mechanical fuel pumps for over 20 years, it was there only car, if it was good enough for him.

 

Good Luck

 

 

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Everyone is talking about alcohol free fuel, but to my knowledge everything in my area is E10 or higher.  I am not aware of any alcohol free fuels available anywhere near where i live in Maine or New Hampshire.   Is there a website to locate stations that sell it?  

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