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Cold weather and engine won't run
https://slantsix.org/forum/viewtopic.php?t=38204		 Page 2 of 3
Author:  sandy in BC [ Sat Dec 05, 2009 8:32 am ]
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OK...it starts and runs fine till it gets too rich and stalls? Then its too rich to start?

Did you try a leaner choke setting?

What do the plugs look like?

The Handymans #2 Secret Weapon is methyl hydrate (wood alcohol). I buy it on one gallon jugs. It cost less than gasolene. Every 2 weeks in winter ...4 tablespoons......

If you ever park your rig and hear a clunk....clunk ....clunk from under the car that is the frozen water in your tank sloshing back and forth. Add alcohol.
Author:  wjajr [ Sat Dec 05, 2009 8:33 am ]
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Your gas smell may be the result of accelerator pump dumping raw gas into the intake manifold during a restart attempt.

I don’t think that carburetor icing will form in 10 to 15 seconds of running in quantities great enough to choke the engine. This is about the time it takes to drain the carburetor fuel bowl. Where stalling problem occurs below 32 degrees I suspect that ice crystals are forming in the gas line, collecting at a filter point, bottom of the bowl, or jet and preventing fuel from passing through to the venture making a lean condition.

Carburetor icing can form at temperatures in the low forties, and is the result of a temperature drop as fuel is atomized. ( There is a learned term for this heat release during a phase change that the thermodynamics guys have, but damned if I can get my head to give it up at the moment, sorry.) If there was a lot of water in the fuel, the engine would also not run well above 32 degrees.

You could try a fuel deicing product that will dry your fuel. I know Dan doesn’t like fuel driers, but thy do work most times if used according to directions, and there is not a lot of moisture in the system. Other wise a tank and carburetor drain and clean maybe needed, as no amount of snake oil will displace a good load of water.

Beware of refueling during, and just after gas station tanks are refilled. If there is any water in their under ground tanks it will be riled up during replenishment, and that water will be pumped into your tank.
Author:  SlantSixDan [ Sat Dec 05, 2009 8:48 am ]
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WJAjr is right on — carb icing tends to occur when ambient temps are in the 40s. Fuel drying additives are fine when used sensibly; the problems are indiscriminate over-use and gross overspending. Sandy's right, buy it from the hardware store labelled as alcohol rather than from the parts store or gas station labelled as "fuel line antifreeze" and you'll spend a lot less. What is called "methyl hydrate" in Canada is called "denatured alcohol" in the States. It is ethanol with about 10% methanol added. Isopropanol (isopropyl alcohol) works, too.

But if you can smell fuel in the exhaust, I'm still more suspicious of the spark supply than of the fuel supply.
Author:  Solotime [ Sat Dec 05, 2009 8:52 am ]
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Dan...how do I tell you which carb I have? What numbers if any are on the carb that would give you that info?
Thanks
Author:  SlantSixDan [ Sat Dec 05, 2009 8:52 am ]
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Snap and post a picture?
Author:  Solotime [ Sat Dec 05, 2009 8:54 am ]
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I have a pic but can't copy and paste it like I am used to.
Author:  Solotime [ Sat Dec 05, 2009 9:05 am ]
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Looking at my past PM's from you Dan it seems as tho you sent me a brand new 1920 1bbl
Author:  SlantSixDan [ Sat Dec 05, 2009 9:27 am ]
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OK, a 1920. That doesn't set off any "Aha!" bells for me. I still think you should check for spark just to make sure you're not headed down a blind alley. And definitely make sure your fuel supply is free of water, because the engine could run for 10-20 seconds on what's in the fuel bowl and then stall if the fuel bowl can't be refilled because the supply is blocked by ice. Next time it won't start, once you've verified spark, spray some carb cleaner down the carb throat and then try again to start it.
Author:  Solotime [ Sat Dec 05, 2009 10:33 am ]
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OK I'll try but why would I get a strong fuel smell from the exhaust if it was starving for fuel due to line freeze? Also I'm sure I can hear the fuel spraying in the carb when I work the throttle from under the hood (after she died)
I will check the spark....just can't see an electrical type failure at about the same time each morning after starting and only when it is below freezing.
Author:  SlantSixDan [ Sat Dec 05, 2009 1:58 pm ]
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It's a perfectly valid question you ask. The fuel in the exhaust could be from the last few "putts" as the engine dies with the choke mostly closed. The point is: if the problem evades solution by quick off-the-top-of-head guesses, it's time to resort to systematic diagnosis, starting with the basics.
Author:  sandy in BC [ Sat Dec 05, 2009 2:22 pm ]
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Quote:
it's time to resort to systematic diagnosis, starting with the basics
Author:  sandy in BC [ Sat Dec 05, 2009 2:31 pm ]
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username SlantSixDan is <UNIGNORED>
Author:  RustyRamcharger [ Sat Dec 05, 2009 6:11 pm ]
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Quote:
I don’t think that carburetor icing will form in 10 to 15 seconds of running in quantities great enough to choke the engine. This is about the time it takes to drain the carburetor fuel bowl. Where stalling problem occurs below 32 degrees I suspect that ice crystals are forming in the gas line, collecting at a filter point, bottom of the bowl, or jet and preventing fuel from passing through to the venture making a lean condition.
If ice crystals were plugging the filter, the carb bowl would be dry and there would be no gasoline odor at the tailpipe. Carb ice can accrete in a few seconds. A small amount of ice in the venturi destroys its function.
Quote:
Carburetor icing can form at temperatures in the low forties, and is the result of a temperature drop as fuel is atomized. ( There is a learned term for this heat release during a phase change that the thermodynamics guys have, but damned if I can get my head to give it up at the moment, sorry.) If there was a lot of water in the fuel, the engine would also not run well above 32 degrees.
Carb ice can form at summertime temperatures. It depends on the relative humidity of the air and the temperature drop in the carb venturi.
Here are a couple of aviation related carb icing charts:
http://www.ntsb.gov/Dockets/Aviation/SE ... 420975.pdf
http://www.atsb.gov.au/media/56519/carb_icing.pdf
Quote:
You could try a fuel deicing product that will dry your fuel. I know Dan doesn’t like fuel driers, but thy do work most times if used according to directions, and there is not a lot of moisture in the system. Other wise a tank and carburetor drain and clean maybe needed, as no amount of snake oil will displace a good load of water.
It is very difficult to find filling stations in the USA that sell pure gasoline. Most all sell gasoline that is diluted with ~10% ethanol. This amount of alcohol eliminates water from the fuel tank without the use of additional alcohol.
Quote:
Beware of refueling during, and just after gas station tanks are refilled. If there is any water in their under ground tanks it will be riled up during replenishment, and that water will be pumped into your tank.
That was a big problem during the switchover to the alcohol blend gasoline. The stations had to have their tanks dried before they could accept deliveries. This problem was discovered when cars that were filled promptly stalled and wouldn't restart after the first delivery to the station.

Is the heat riser valve working? How about the intake air preheat system (exhaust manifold shroud, duct, and thermostatically controlled door in the air cleaner intake)? If the air preheat system is malfunctioning or inoperative, carburetor icing will occur.

Ken
:-)
Author:  Solotime [ Mon Dec 07, 2009 11:16 am ]
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Looks like the culprit is going to be ice. Checked the spark and it tested fine.
After she died this morning and would not re-fire I dumped a teaspoon of gas down the carb and she tried to run. Did this a couple times to verify she was not getting any gas.
So I went and got my forced air propane heater from the shop and set it up on top of the radiator to blow warm air onto the carb. Did that for 15 minutes until the carb felt completely warmed and with a couple pumps the truck fired up and ran fine. 22 degrees at the time.
So I put in a bottle of HEET which was what I had on hand and drove it around plus idling for at least 30 minutes. The proof will be if she starts in the morning or even this evening.
Thanks Guys
Author:  SlantSixDan [ Mon Dec 07, 2009 11:28 am ]
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Very fine — carry on adding reasonable amounts of alcohol to your fuel until the problem goes away. Remember to keep the fuel tank as full as possible at all times in cold weather, to minimise condensation. And you may want to look at Aggressive Ted's fuel/water separator idea, though I still have some qualm about crash safety with such a device under the hood.
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