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genny and or gas question [message #133963] Sat, 09 July 2011 19:09 Go to next message
chasingsummer is currently offline  chasingsummer   United States
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Registered: May 2011
Location: asheboro, nc
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75 eleganza 2, 6000 genny
last weekend i finally got ginny starting from inside coach, i even ran both roof ac's for better part of day. i think it ran out of gas and stopped.
today, i thought i would add a gallon of gas and see how long genny would run with one ac on. after an hour i turned it off.
my main question is , assuming i did run tanks low enough that genny had no gas, when i added the one gallon, did half go in each tank so only half gallon was available for genny?
with one ac running mid cool, and assuming genny ir running good, how long should it run on a gallon of gas?
any input which helps my light bulb burn brighter is appreciated, i was hoping to see how long a gallon would be good for with one ac running and i dont think i learned anything
thansk bgk


brian asheboro, nc 75 eleganza, 74 build 119k miles and counting, DOG HOUSE
Re: genny and or gas question [message #133967 is a reply to message #133963] Sat, 09 July 2011 19:17 Go to previous messageGo to next message
Ken Burton is currently offline  Ken Burton   United States
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Registered: January 2004
Location: Hebron, Indiana
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If it was sitting still when it ran out of gas and you added one gallon then you do not care where the gallon went. Run it until it quits again and you have used one gallon.

Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
Re: genny and or gas question [message #134017 is a reply to message #133963] Sun, 10 July 2011 09:29 Go to previous messageGo to next message
Matt Colie is currently offline  Matt Colie   United States
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Location: S.E. Michigan
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chasingsummer wrote on Sat, 09 July 2011 20:09

75 eleganza 2, 6000 genny
last weekend i finally got ginny starting from inside coach, i even ran both roof ac's for better part of day. i think it ran out of gas and stopped.
today, i thought i would add a gallon of gas and see how long genny would run with one ac on. after an hour i turned it off.
my main question is , assuming i did run tanks low enough that genny had no gas, when i added the one gallon, did half go in each tank so only half gallon was available for genny?
with one ac running mid cool, and assuming genny ir running good, how long should it run on a gallon of gas?
any input which helps my light bulb burn brighter is appreciated, i was hoping to see how long a gallon would be good for with one ac running and i dont think i learned anything
thansk bgk

Brian,

You have asked about six questions and I have only a non-answer to one of those.

The fuel fill plumbing of a GMC makes the destination of fuel poured in an absolute crap-shoot. It is very dependent on the coach's attitude (not whether she is having a good day, but roll left-right and pitch up-down). The only thing that I think you can be certain of is that the gallon you added did not put more than one gallon in the main (rear) tank.

I track my coach's fuel consumption to an outrageous degree. But I have never been able to reliably separate the APU fuel use from road consumption. I do plan to set up and run from an isolated tank some day, but that will wait until I get several other fires stomped out.

Matt


Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
Re: [GMCnet] genny and or gas question [message #134022 is a reply to message #134017] Sun, 10 July 2011 09:54 Go to previous messageGo to next message
Robin Hood is currently offline  Robin Hood   United States
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If there are two gas tanks, why are there not two gas gauges?

Robin


--
Robin Hood
Jackson, MS
2003 Buick Lesabre
1968 Pontiac Catalina
1978 GMC Royale motorhome
1977 GMC Palm Beach motorhome
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Re: [GMCnet] genny and or gas question [message #134024 is a reply to message #134022] Sun, 10 July 2011 10:16 Go to previous messageGo to next message
James Hupy is currently offline  James Hupy   United States
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Robin, there are two senders. When you change the rocker switch from one
tank to the other, you also change the current path to the other sender. No
need for two gages. But the tanks share a common filler manifold, and fuel
does migrate between tanks when the coach is in motion. Set the selector
switch on main, and drive till the low fuel warning light comes on, switch
to aux and start hunting for a gas station. It is what I do. One further
caution, when you are low on fuel on the main tank and have that one
selected and you decend a steep grade, it is possible to uncover the fuel
pickup in that tank and have the engine quit, with the result that you have
no vacuum boost to operate the brake booster. A 12,500 # vehicle without
vacuum assisted brakes is a real challenge to stop. This has happened to me,
and it ain't no fun.
Jim Hupy
Salem, OR
78 GMC Royale 403

On Sun, Jul 10, 2011 at 7:54 AM, Robin Hood <loxley@gmail.com> wrote:

> If there are two gas tanks, why are there not two gas gauges?
>
> Robin
>
>
> --
> Robin Hood
> Jackson, MS
> 2003 Buick Lesabre
> 1968 Pontiac Catalina
> 1978 GMC Royale motorhome
> 1977 GMC Palm Beach motorhome
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
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Re: [GMCnet] genny and or gas question [message #134030 is a reply to message #133963] Sun, 10 July 2011 11:23 Go to previous messageGo to next message
powerjon is currently offline  powerjon   United States
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Registered: January 2004
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Brian,

To get a picture on how the gas goes into the tanks see:

http://gmcmotorhomeinfo.com/tank.html

It is a real good explanation on how the fuel system works on the GMC
finished coaches. Coaches that were finished by others did not alway
allow the generator to draw fuel in the same way and could suck your
tanks totally dry and leave you stranded.

It would be difficult to determine if you got that entire gallon of
gas into the main tank which the generator draws from. Note that the
generator will quit when the main tank is aprox. 1/4 full and on level
ground. If you were tilted things change.

Regards,

J.R. Wright
GMC GreatLaker
78 Buskirk 30' Stretch
1975 Avion (Under Reconstruction)
Michigan

On Jul 9, 2011, at 8:09 PM, brian wrote:

>
>
> 75 eleganza 2, 6000 genny
> last weekend i finally got ginny starting from inside coach, i even
> ran both roof ac's for better part of day. i think it ran out of gas
> and stopped.
> today, i thought i would add a gallon of gas and see how long genny
> would run with one ac on. after an hour i turned it off.
> my main question is , assuming i did run tanks low enough that genny
> had no gas, when i added the one gallon, did half go in each tank so
> only half gallon was available for genny?
> with one ac running mid cool, and assuming genny ir running good,
> how long should it run on a gallon of gas?
> any input which helps my light bulb burn brighter is appreciated, i
> was hoping to see how long a gallon would be good for with one ac
> running and i dont think i learned anything
> thansk bgk
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist

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J.R. Wright
GMC GreatLaker
GMC Eastern States
GMCMI
78 30' Buskirk Stretch
75 Avion Under Reconstruction
Michigan
Re: genny and or gas question [message #134032 is a reply to message #133963] Sun, 10 July 2011 11:38 Go to previous messageGo to next message
idrob is currently offline  idrob   United States
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Registered: January 2005
Location: Central Idaho
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chasingsummer wrote on Sat, 09 July 2011 17:09

75 eleganza 2, 6000 genny
last weekend i finally got ginny starting from inside coach, i even ran both roof ac's for better part of day. i think it ran out of gas and stopped.
today, i thought i would add a gallon of gas and see how long genny would run with one ac on. after an hour i turned it off.
my main question is , assuming i did run tanks low enough that genny had no gas, when i added the one gallon, did half go in each tank so only half gallon was available for genny?
with one ac running mid cool, and assuming genny ir running good, how long should it run on a gallon of gas?
any input which helps my light bulb burn brighter is appreciated, i was hoping to see how long a gallon would be good for with one ac running and i dont think i learned anything
thansk bgk


I did a forum search and found this:

On Sun, 18 Jul 2010 23:05:09 -0500 "Charles" <gcw13@sbcglobal.net>
writes:
> Does anybody know what is the average gas
> consumption of a 6000 watt onan is per hour.
> It seems like this was covered a couple years ago
> but I don't find it anywhere.
> Charles

The spec is in the onan manual but as I recall it is 1/2 GPH at half load
and 3/4 GPH at full load.

The manual might be found at Billys Massey's most excellent Publications
site.
>



Rob Allen
former owner of '76 x-PB
Re: genny and or gas question [message #134035 is a reply to message #133963] Sun, 10 July 2011 12:27 Go to previous messageGo to next message
WD0AFQ is currently offline  WD0AFQ   United States
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Location: Dexter, Mo.
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Senior Member
Rob, I find that fairly accurate running the only roof air that we have. 1/2 gallon per hour is about right.
Dan


3 In Stainless Exhaust Headers One Ton All Discs/Reaction Arm 355 FD/Quad Bag/Alum Radiator Manny Tran/New eng. Holley EFI/10 Tire Air Monitoring System Solarized Coach/Upgraded Windows Satelite TV/On Demand Hot Water/3Way Refer
Re: [GMCnet] genny and or gas question [message #134044 is a reply to message #134017] Sun, 10 July 2011 13:43 Go to previous messageGo to next message
Byron Songer is currently offline  Byron Songer   United States
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Registered: August 2007
Location: Louisville, KY
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Senior Member

Good question, Brian. Good response, Matt.

There are too many variables involved to give a definitive answer. For
Onan's current line of gensets they do quote fuel consumption based on load
ratings.

The rule of thumb for the 6KW Onan made in the 70's was "about a gallon per
hour". It depends on how much the A/C is calling for 110, the type of fuel
being consumed, etc. Of course, what the A/C does (how much the compressor
runs) depends on the ambient air temperature and relative humidity. Your
mileage will vary.

The other variable regarding your "test" was, as Matt mentions, where the
portion of the gallon you added ultimately wound up and was the coach move
any between the previous time on and the test conducted after adding a
gallon.

Byron

Matt Colie wrote:

>
>
> chasingsummer wrote on Sat, 09 July 2011 20:09
>> 75 eleganza 2, 6000 genny
>> last weekend i finally got ginny starting from inside coach, i even ran both
>> roof ac's for better part of day. i think it ran out of gas and stopped.
>> today, i thought i would add a gallon of gas and see how long genny would run
>> with one ac on. after an hour i turned it off.
>> my main question is , assuming i did run tanks low enough that genny had no
>> gas, when i added the one gallon, did half go in each tank so only half
>> gallon was available for genny?
>> with one ac running mid cool, and assuming genny ir running good, how long
>> should it run on a gallon of gas?
>> any input which helps my light bulb burn brighter is appreciated, i was
>> hoping to see how long a gallon would be good for with one ac running and i
>> dont think i learned anything
>> thansk bgk
>
> Brian,
>
> You have asked about six questions and I have only a non-answer to one of
> those.
>
> The fuel fill plumbing of a GMC makes the destination of fuel poured in an
> absolute crap-shoot. It is very dependent on the coach's attitude (not
> whether she is having a good day, but roll left-right and pitch up-down). The
> only thing that I think you can be certain of is that the gallon you added did
> not put more than one gallon in the main (rear) tank.
>
> I track my coach's fuel consumption to an outrageous degree. But I have never
> been able to reliably separate the APU fuel use from road consumption. I do
> plan to set up and run from an isolated tank some day, but that will wait
> until I get several other fires stomped out.
>
> Matt


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-- Byron Songer
Full-timing to enjoy the USA
Former owner but still an admirer
GMC paint schemes at -
http://www.songerconsulting.net
Re: genny and or gas question [message #134060 is a reply to message #133963] Sun, 10 July 2011 15:29 Go to previous messageGo to next message
Carl S. is currently offline  Carl S.   United States
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Registered: January 2009
Location: Tucson, AZ.
Karma: 13
Senior Member

I'm not sure this is relevant to this discussion, but I have an (Onan) engine driven, mid 80's vintage, Miller 200 amp welder/5K auxiliary power generator that I have used on construction sites, where temporary power was not available. It is mounted on a small trailer and has a ~ 13 - 14 gallon gas tank on it. We used this machine for approx. 8 hours/day, 5 days/week for weeks on end. I would have to fill up the tank every three days or it would run dry at some point on the fourth day. This is also an 1,800 rpm machine (in APU mode) and was used to power worm drive Skilsaws, 1/2" drive drills, electric impact wrenches, Sawzalls, etc. These tools were not operating constantly, obviously, but the generator probably had a 1/3 to 1/2 (maybe less) load on it most of the time. It used an average of 3.5 gallons of gas per day.

Carl Stouffer '75 ex Palm Beach Tucson, AZ. Chuck Aulgur Reaction Arm Disc Brakes, Quadrabags, 3.70 LSD final drive, Lenzi knuckles/hubs, Dodge Truck 16" X 8" front wheels, Rear American Eagles, Solar battery charging. GMCSJ and GMCMI member

[Updated on: Sun, 10 July 2011 15:38]

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Re: genny and or gas question [message #134074 is a reply to message #133963] Sun, 10 July 2011 18:24 Go to previous messageGo to next message
chasingsummer is currently offline  chasingsummer   United States
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Location: asheboro, nc
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Senior Member
my test so far, and this is with front end slighlty lower than the rear,
twice i ran genny for one hour time period and mid ac unit on mid cool. upper 80's outside and coach is not under cover.
the second hour i ran my radio for noise.
i do not know if one ac is half load, or maybe third load, i am sure i could figure that out but the people who know me know i am too lazy to take such experiment that serious. my aim was to try and understand how much gas is used say for example if running genny for roof ac while driving down road, as well as rough idea on overnite trip without hookups. to me running genny for roof ac while driving, the gas usage has to be marginal. if 1 gallon runs 2 hours, then during that 2 hours driving i have added one gallon or 2 to to fil up. while sitting, i would assume once sun is down and things are cooling off, the genny would not be needed all night, but even with our high gas cost, truely worth the maybe 3 gallons to stay cool all night.
i assume once home from work tomorrow i will restart and see if i can get the 3rd hour before out of gas,


brian asheboro, nc 75 eleganza, 74 build 119k miles and counting, DOG HOUSE
Re: genny and or gas question [message #134079 is a reply to message #134017] Sun, 10 July 2011 19:44 Go to previous messageGo to next message
bukzin is currently offline  bukzin   United States
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Location: North California
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I have learned the hard (best) way regarding fuel.


If my gas gauge shows near 1/4 full I look for
a filling station.

If it get below 1/8 trouble is near.



A friends GMC ran out while going up hill and it
seem to take 5 gallons from the tow truck to get it started.


Bukzin
1977 Palm Beach
Re: [GMCnet] genny and or gas question [message #134086 is a reply to message #134024] Sun, 10 July 2011 20:17 Go to previous message
jhbridges is currently offline  jhbridges   United States
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Location: Braselton ga
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I do the low wing thang... run it an hour on the cranmk tank - usually main, then swap and run it till I get a light or a sputter, then switch back to the ne I started with.
 
--johnny


--- On Sun, 7/10/11, James Hupy <jamesh1296@gmail.com> wrote:




Robin, there are two senders. When you change the rocker switch from one
tank to the other, you also change the current path to the other sender. No
need for two gages. But the tanks share a common filler manifold, and fuel
does migrate between tanks when the coach is in motion. Set the selector
switch on main, and drive till the low fuel warning light comes on, switch
to aux and start hunting for a gas station.
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Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons. Braselton, Ga. I forgive them all, save those who hurt the dogs. They must answer to me in hell
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