[AT] oil change

Cecil Bearden crbearden at copper.net
Fri Dec 7 16:56:34 PST 2007 

During the Ice storm of Jan-Feb2001 here in Central OK, we were running 
on a generator. It had a 6 cyl continental and was only 15KW.  We had 
about 2 inches of ice on everything for 10 days before it began to thaw 
out.  About 2am, the generator would develop an icing problem.  It would 
slow down to about 30 cycles. The carburetor would have about 2 inches 
of frost on the outside. The first time, I held a torch under the 
carburetor to get it warm enough that I could get back inside the barn 
and warm up and figure out what to do.  I found a 5 gallon can of 
Methanol, and put a gallon in the gas tank of the generator.  In about 2 
minutes it started running great.  Our electric coop was selling Coleman 
generators since they had about 5 thousand customers out of electricity 
and later about 350,000 poles down.  The Coleman rep said to use Premium 
gas in the generators or use gas drier because regular unleaded has a 
lot of water in it and a surfactant to keep it mixed..    We mixed a 
gallon of Methanol to 30 gallons of gas twice a day for 10 days then 
bought a diesel generator.   Since then I have rebuild a lot of Onan 2 
cylinder engines on fire pumps.  To get the volume and pressure from the 
pump to meet the certification requirements, we have to use Premium 
unleaded.  On a 20 hp engine running a 21/2 inch pump, the premium will 
increase the pressure fmom about 95 lbs to 135...   That is a big 
difference!!!!

Cecil in OKla

Larry D Goss wrote:
> Good article, Will.  Yes, it's the condensation of moisture inside the 
> carburetor that does the damage.  By the time you see ice on the outside of 
> the carburetor, things are really cold on the inside.
>
> I'm reminded of a knuckle-biting situation I found myself in one night in 
> Oklahoma.  A group of us (faculty) were teaching a night course in 
> Bartlesville when an ice storm hit.  We headed to the airfield for a return 
> flight to Stillwater only to find that there was nearly a quarter inch of 
> ice on all the surfaces.  The pilot (Hoyt Walkup) had us pile in and he 
> proceeded to race the plane (an ancient twin Beech) up and down the runway 
> several times to no effect.  He would get up to takeoff speed and then shut 
> down the engines in time to stop and turn around to go through the process 
> once again.  Each time, he would shine his flashlight out the window and 
> check the condition of the ice.  Finally, he said, "OK, I think we can make 
> it on this trip."  And we headed down the airstrip one more time.  We were 
> well beyond the point of no return when the ice suddenly turned to water and 
> we were airborne.  I asked Hoyt why he didn't turn on the deicer?  The plane 
> had been assembled out of three old planes and none of them had an operating 
> deicer system.  So there was no system to turn on!  The heat buildup on the 
> very front edge of the wings was enough to melt the ice at that point, and 
> once the front edge was gone there was nothing to keep the remainder of the 
> ice from peeling off the lift surfaces.  I suspect there were stains left in 
> everybody's shorts that evening.
>
> Larry
>
> ----- Original Message ----- 
> From: "William Powell" <william.neff.powell at comcast.net>
> To: "'Antique tractor email discussion group'" 
> <at at lists.antique-tractor.com>
> Sent: Friday, December 07, 2007 4:46 PM
> Subject: Re: [AT] oil change
>
>
>   
>> Larry,
>>
>> No, that's not what I think I said.... At this point I can't be sure of
>> anything... Sorry for the bad English, writing was never my strong
>> subject....
>>
>> Here's what I found and I think they make a different point about energy
>> consumption causing icing due to air pressure changes, not gasoline 
>> crossing
>> a phase barrier...:
>> http://www.flycorvair.com/carbice.html
>>
>>
>>
>>
>> "Ice can form on warm days. Anytime a gas expands from high pressure to 
>> low
>> it will consume energy from its environment. In this case, the gas is the
>> air the engine is consuming and the pressure drop is from ambient to
>> manifold  pressure, about 30"map to 12"map. The energy it consumes is any
>> form of     available heat. Most of the heat comes out of the air. This
>> temperature drop  is instantaneous and can easily be more than 40F. Shoot 
>> a
>> thermometer with a  CO2 extinguisher and learn."
>>
>> But, in section 5 they kind of make the point I was trying to make....
>>
>>    "Misted fuel is still a liquid, not a vapor. 100LL under these
>>    conditions remains a mist until reaching the combustion chamber.
>> Contrast
>>    this with auto fuel, which by design will vaporize readily under these
>>    circumstances. It is a fact of physics that when the fuel changes from 
>> a
>>
>>    liquid mist to a gaseous vapor, it takes further heat from the
>> surrounding
>>    air. This is the cooling one feels when gas evaporates off the skin.
>> This
>>    additional temperature drop can produce icing when the same engine 
>> under
>>
>>    identical circumstances would not ice with 100LL."
>>
>>
>>
>>
>>
>> I guess I did not really know what carb icing was, I just noticed the 
>> frost
>> on my WD when I plow snow, looks like it can effect the inside of the carb
>> and be quite a problem on a plane....
>>
>>
>> Regards,
>>
>> Will
>>
>> -----Original Message-----
>> From: at-bounces at lists.antique-tractor.com
>> [mailto:at-bounces at lists.antique-tractor.com] On Behalf Of Larry D Goss
>> Sent: Friday, December 07, 2007 5:11 PM
>> To: Antique tractor email discussion group
>> Subject: Re: [AT] oil change
>>
>> Carburetor icing is frozen gasoline?  Now that, I want to see.  That may 
>> not
>> be what you intended to say, but that's what I think I see.
>>
>> Larry
>>
>> ----- Original Message -----
>> From: <william.neff.powell at comcast.net>
>> To: "Antique tractor email discussion group" 
>> <at at lists.antique-tractor.com>
>> Sent: Friday, December 07, 2007 12:32 PM
>> Subject: Re: [AT] oil change
>>
>>
>>     
>>> >From little chemistry I had in college I always thought that the frost 
>>>       
>>>> on
>>>>         
>>>> the carb was from the vaporization of the gasoline. I remember that when
>>>> a liquid crosses the phase barrier to a gas it takes a lot of energy to
>>>> cross... So, as with freon, when gas evaporates, heat energy is taken
>>>> during the conversion which cools off the carb.
>>>>         
>>> Also, many old tractors do not have heat risers, so, the dense cold air
>>> coming in does not  help the gas evaporate, so, you stall out unless you
>>> force more fuel in by putting on the choke. Eventually the manifolds heat
>>> up and your fine, slow speeds, low wind.. For an old tractor lover this 
>>> is
>>>       
>>> a minor inconvenience, but probably unacceptable for most auto drivers
>>> zooming down the road at 60 cooling off their manifolds.
>>>
>>> As far as the injectors, aren't most of them spraying in right at the
>>> manifold near the head? That area probably heats up fast.
>>>
>>>
>>>
>>>
>>>
>>> -------------- Original message ----------------------
>>> From: Ralph Goff <alfg at sasktel.net>
>>>       
>>>> ----- Original Message ----- 
>>>> From: "Larry D Goss" <rlgoss at evansville.net>
>>>> To: "Antique tractor email discussion group"
>>>> <at at lists.antique-tractor.com>
>>>> Sent: Friday, December 07, 2007 11:40 AM
>>>> Subject: Re: [AT] oil change
>>>>
>>>>
>>>>         
>>>>> Question of the day -- does carburetor icing occur on fuel injected
>>>>> engines?
>>>>> :-)
>>>>>           
>>>> Hi Larry
>>>> If icing does occur in fuel injected engine I have never noticed it. My
>>>> 97
>>>> Blazer starts and runs smoother than any carbureted engine I have ever
>>>> known. No stumbling or hesitation, no black smoke and stalling. I don't
>>>> know
>>>> how they do it but it works.
>>>>
>>>> Ralph in Sask.
>>>>
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