Vaporlock and the ensuing conversations

[Kevin in NJ]

But if you have fuel purculating in the bowl forcing the float up preventing fuel flow is that vapor lock?

[George Miller]

Originally Posted by RockHillWill

Jeez, guys, what's the big deal here???? When a liquids is changed to a gas it is vaporized. It makes no difference if you have a fuel pump, a gas tank 10 feet tall or a carburetor too close to the heat. If the fuel stops flowing because of vapor ANYWHERE, caused by ANYTHING, the darn thing is vapor locked!

Plus 1 I'm with you.

[Dick Steinkamp]

Webster's says vapor lock is...

"partial or complete interruption of flow of a fluid (such as fuel in an internal combustion engine) caused by the formation of bubbles of vapor in the feeding system"

https://www.merriam-webster.com/dictionary/vapor%20lock

[Dick Steinkamp]

Originally Posted by Kevin in NJ

But if you have fuel purculating in the bowl forcing the float up preventing fuel flow is that vapor lock?

I'm not sure how the fuel vaporizing in the float bowl would force the float up. Isn't the float bowl vented?

[Gold Digger]

I know this, I had a 29 that the engine would die driving down the road and I would loosen the gas line at the carb and steam would spew out for a second or two then liquid would run out. I could restart and go for a few miles and same thing again. Put 4 cloths pins on the line and it never occurred again. Thinking back that car had a copper gas line on it and I wonder if that may have contributed to the problem.

[steve s]

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Originally Posted by Dick Steinkamp

Webster's says vapor lock is...

"partial or complete interruption of flow of a fluid (such as fuel in an internal combustion engine) caused by the formation of bubbles of vapor in the feeding system"

https://www.merriam-webster.com/dictionary/vapor%20lock

No fair, Dick!

[Big hammer]

Very interesting thread! My post when my A would start hot, i pull the choke and it starts !
With my riding lawn mower I also find the same thing, running it hard, then stop for a break, if it won't start hot, I pull the choke, it starts and I'm back mowing! Should I fix a problem or just get it running again as quickly as possible? One of the advantages of having a manual choke!

[RockHillWill]

Man, it's been a long time, since I've had this much fun!!!

Yes, If vapor is contributing to the stoppage of fuel flow it is vapor locked.

If you don't not have a key, does it really matter what kind of a lock it is????

[CT Jack]

3 possible causes for fuel flow related problem:
1. Fuel contaminated with water
2. Ethanol vaporizing causing poor to no flow of fuel to engine
3. Carburetor has a marginal high speed jet flow rate. Low flow is restricting higher engine speeds. Float level needs adjusting
Solution for 1 & 2 - empty fuel tank, install 89 or 93 grade gas, and add some Marvel Mystery Oil to fuel.

[Tom Wesenberg]

Originally Posted by George Miller

Plus 1 I'm with you.

Plus 2

I used to think vapor lock couldn't happen in a gravity feed system until it happened to my friend while I was riding with him, and then a couple weeks later it happened to me in my 28.

It even happened on a hot day while the car was parked for 3 hours, and all the fuel boiled away in the carb and fuel line. I turned the tank valve back on, but fuel wouldn't start flowing until I removed the line at the carb, then I reconnected it and drove away. This same thing happened twice in one day.

[bobbycoke]

My pop was a Ford employee in the late 30's and early 40's after the war was a Ford dealer service manager and twice we had vapor lock on vacation in his 1953 Ford [his first new car he bought because they were doing away with the flathead the next year] when in the southwest with real hot temps..........first time was near a lttle fruit and veggie stand......he walked over while car cooled [as much as it could in 100 degree weather ] got 2 grapefruits cut them halve way through and straddled the fuel line with them by the carb.........no more Vaporlock that day !!!!!!!!!!!! The next time it happened [another southern vacation] he went to the trunk and pulled out a package of wooden clothespins [the spring type ] and put them the fuel line another cheap "heat sink" that really impressed a 7-8 year old kid who knew Dad could fix anything with nothing!!!!!!!!!! He had planted the clothespins for suck an occasion.........LOL .......great memories brought up by this thead.......bobbycoke

[steve s]

Whenever I find myself feeling too mystified about how some people can deny vapor lock can occur in a Model A because they've never personally seen it, I try to remind myself that that's how I feel about the clothes pin thing. How can that possibly work!? Wood is a terrible heat conductor and heat sink. But a lot of people swear by it.

I would point out, however, that the clothes pins (or the grapefruit halves) are applied to a fuel line, not a fuel pump.

[Benson]

...

[stouchton]

Good article below.... fact checked as much as I could at lunch time and seems to check out well.

Also - ethanol fuel will burn leaner, engine runs hotter - contributing to the problem.

Noticed the leaner condition on an engine I was setting up using an air/fuel meter. Actually changed the main jetting based upon type of fuel. So... on the A you probably could compensate with the GAV - I never tried this when I had an issue. Removing my thermostat solved my problem, and I can run E10 though the engine has more pep on the straight stuff!!!

http://www.militarytrader.com/milita...other-gas-woes

[Flathead]

How about this?? What if you soak the wooden clothes pins in water first, then when you clamp them on the fuel line the water evaporating from the wood will give an extra boost to the cooling effect. Armchair scientists may now chime in.

[steve s]

Originally Posted by Flathead

How about this?? What if you soak the wooden clothes pins in water first, then when you clamp them on the fuel line the water evaporating from the wood will give an extra boost to the cooling effect. Armchair scientists may now chime in.

I'm not sure if you're serious or not, but in case you are--and speaking as an actual scientist but an armchair mechanic--the water would not only give an "extra boost to the cooling effect," but would constitute the totality of the cooling effect. Of course, because wood doesn't absorb much water, the effect would be very short lived. I've never seen anyone who claimed that the clothes pin trick worked mention the need to first soak them.

[RUNNERBUN]

The thing I see that all arguments have in common is "HEAT" and "HIGH TEMPERATURE" Be it called Vaporlock. Boiling Carb or any other name you may wish to use, the effect is the same. Rough running engine, lack of power or just plain stopping alltogether.
I experienced the problem for the first time after I had run up a total of over 80,000 km and did not believe the problem was vaporlock. Removed Carb from the car several times to do a complete inspection and found nothing out of place. Each time when I reinstalled the Carb it ran perfectly until the engine got up to temp again. I then tried lightly spraying the Carb with water when I came to a stop and the problem was fixed.
I therefore concluded that the problem was indeed caused by overheating of the Carb and also possibly contributed by the unknown quality of the fuel as I was at the time travelling away from my home State and at best some fuel is of suspect quality.
I live in the tropics so I'm no stranger to high temps. yet I never experienced vaporlock???? while driving at home. Just my 2 cents worth.

[DC 69]

Related to ethanol, vapor lock, and just thought I would ask: Has anyone thought of using AV-Gas (aviation fuel)? Pros vs Cons, etc.

[RockHillWill]

For those that still don't believe in vapor lock:

https://sciencing.com/two-types-vapo...n-8676696.html

[Benson]

Originally Posted by DC 69

Related to ethanol, vapor lock, and just thought I would ask: Has anyone thought of using AV-Gas (aviation fuel)? Pros vs Cons, etc.

There is a hefty fine for using AV Gas in a car driven on public highways!

There is no road tax on AV gas and the Department of Revenue gets POed when they find out that you are driving on public roads and NOT paying Road Tax.