| [GMCnet] Generator stopping when it should not [message #261105] |
Sat, 06 September 2014 18:43  |
Neil Fonville
Messages: 68
Registered: May 2014
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I have a bit newer Onan that stops randomly. I'm about certain it's due to fuel starvation. The inline fuel filter is always dry when it happens. I replaced a bad fuel pump and it does pump fuel when power is applied to it.
I ran new rubber tubing and it made no difference. I noticed when changing the tubing that with a full tank of gas, it did not flow real freely. When I removed the rubber from the metal tube coming from the tank, only small amounts of fuel ran out on the ground.
My question is: Is there a problem with running a metal wire in the metal tube to the tank? I thought running a fine wire in there might clear out the obstruction.
Any other ideas or suggestions? Thanks for everyone's help.
Neil Fonville
Allen, TX
1975 GMC II
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1975 GMC II
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| Re: [GMCnet] Generator stopping when it should not [message #261106 is a reply to message #261105] |
Sat, 06 September 2014 19:24  |
C Boyd
Messages: 2629
Registered: April 2006
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sir, you might remove the gas fill cap and shoot short bursts of shop air back into the tank.
Neil Fonville wrote on Sat, 06 September 2014 19:43I have a bit newer Onan that stops randomly. I'm about certain it's due to fuel starvation. The inline fuel filter is always dry when it happens. I replaced a bad fuel pump and it does pump fuel when power is applied to it.
I ran new rubber tubing and it made no difference. I noticed when changing the tubing that with a full tank of gas, it did not flow real freely. When I removed the rubber from the metal tube coming from the tank, only small amounts of fuel ran out on the ground.
My question is: Is there a problem with running a metal wire in the metal tube to the tank? I thought running a fine wire in there might clear out the obstruction.
Any other ideas or suggestions? Thanks for everyone's help.
Neil Fonville
Allen, TX
1975 GMC II
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C. Boyd
76 Crestmont
East Tennessee
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| Re: [GMCnet] Generator stopping when it should not [message #261165 is a reply to message #261105] |
Sun, 07 September 2014 09:07 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
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Neil Fonville wrote on Sat, 06 September 2014 19:43I have a bit newer Onan that stops randomly. I'm about certain it's due to fuel starvation. The inline fuel filter is always dry when it happens. I replaced a bad fuel pump and it does pump fuel when power is applied to it.
I ran new rubber tubing and it made no difference. I noticed when changing the tubing that with a full tank of gas, it did not flow real freely. When I removed the rubber from the metal tube coming from the tank, only small amounts of fuel ran out on the ground.
My question is: Is there a problem with running a metal wire in the metal tube to the tank? I thought running a fine wire in there might clear out the obstruction.
Any other ideas or suggestions? Thanks for everyone's help.
Neil Fonville
Allen, TX
1975 GMC II
Neil,
Yes, you should be able to do that, if the fuel line is like GMC OE. But, if it pumped fuel, that is probably not your problem.
The fuel line from the tank is a negative head. When disconnected, no fuel should run out unless you take the line end below the tank level and start a siphon.
My immediate suggestion would be to run the fuel pump into a clean can. See if it is blowing bubbles. That would mean that there is a leak in the line above the tank level.
Where is the filter that is going dry?? It is not a stock GMC part, but frequently added in the line on the way to the APU (genset). If it is in the line before pump, and it is going dry, then you are either below 1/4 tank (the fuel pick-up for the APU is higher than the main so you can't run your self out of fuel by running the APU) or you have a bad joint on the way there.
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
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| Re: [GMCnet] Generator stopping when it should not [message #261194 is a reply to message #261168] |
Sun, 07 September 2014 13:17 |
Neil Fonville
Messages: 68
Registered: May 2014
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Ok, So I disconnected the rubber line at the fuel pump of the genset and
blew air in with the compressor. I could hear air escaping from the
filler. Hooked it back up and it ran fine but I don¹t think it¹s fixed.
Did not blow air through the inline filter.
The filter is a clear inline installed 3 inches from the fuel pump input.
It never really fills up and looks like it was going to run dry. The
coach tank is full of gas so I know I¹m not dealing with that.
I had installed new rubber line from where the metal line from the tank
begins. There was an old ³AC² fuel filter in line. It was really old.
Took it out and cut it open. It was really clogged and dirty so I though
that would be the problem for sure. But I guess it could not be that easy.
So does there need to be another filter besides the one installed on the
generator itself? It has a small one past the fuel pump but before the
carb.
I will try the pump fuel into a can and look for bubbles when I go back
out later this week.
Thanks,
Neil
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1975 GMC II
Allen, TX
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| Re: [GMCnet] Generator stopping when it should not [message #261195 is a reply to message #261106] |
Sun, 07 September 2014 13:30 |
Otterwan
Messages: 946
Registered: July 2013
Location: Lynnwood (north of Seattl...
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C Boyd wrote on Sat, 06 September 2014 17:24sir, you might remove the gas fill cap and shoot short bursts of shop air back into the tank.
I'd be really careful if you choose to do this. You might accidentally pop a fuel line off that you can't get to without dropping the tanks. Better to blow air through form the generator fuel line, and use something other than 100 psi shop air if you have it.
1977 Birchaven, Lynnwood WA - "We may not be able to stop all evil in the world, but I know that how we treat one another is entirely up to us."
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| Re: [GMCnet] Generator stopping when it should not [message #261202 is a reply to message #261199] |
Sun, 07 September 2014 14:57 |
Jim Miller
Messages: 501
Registered: March 2008
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Have you tried temporarily bypassing the inline filter? Or perhaps installed a new one?
Have you tried running the Onan via a gas can instead of the vehicle tank? If so does the stalling problem recur?
Have you tried Matt's suggesting of directing the pump's output into a can to ensure you get good flow with no bubbles?
These first steps will help you find - or let you rule out - a fuel delivery problem.
If delivery of the raw fuel is OK then you can start looking at the carb - we worked on one here at the compound that would run for a bit and then fall over - each time it died we found it had a dry bowl. We ruled out fuel delivery using the steps above and thus narrowed it down to the carb. Upon examining the needle and seat we found the seat had a tiny flap of material that had torn loose which would occasionally make its way over the hole and completely block the flow of fuel into the bowl.
However - don't worry about the carb until you confirm positive delivery of fuel.
--Jim "saving the lives of Onans one unit at a time" Miller
1977 Eleganza II
1977 Royale
Hamilton, OH
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Jim Miller
1977 Eleganza II
1977 Royale
Hamilton, OH
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| Re: [GMCnet] Generator stopping when it should not [message #261205 is a reply to message #261202] |
Sun, 07 September 2014 16:01 |
Neil Fonville
Messages: 68
Registered: May 2014
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I have by passed the inline filter and same result which it died 30
minutes of use. Purrs like a kitten when running but dies. Pulled the
fuel line and it was dry going into the fuel pump.
I have not tried an external tank. I was thinking of picking up a 6 gal
boat tank.
I will try the bubbles test this week.
Thanks everyoneŠ.I¹ll report back after the two tests.
Neil
On 9/7/14, 2:57 PM, "Jim Miller" wrote:
> Have you tried temporarily bypassing the inline filter? Or perhaps
> installed a new one?
>
> Have you tried running the Onan via a gas can instead of the vehicle
> tank? If so does the stalling problem recur?
>
> Have you tried Matt's suggesting of directing the pump's output into a
> can to ensure you get good flow with no bubbles?
>
> These first steps will help you find - or let you rule out - a fuel
> delivery problem.
>
> If delivery of the raw fuel is OK then you can start looking at the carb
> - we worked on one here at the compound that would run for a bit and then
> fall over - each time it died we found it had a dry bowl. We ruled out
> fuel delivery using the steps above and thus narrowed it down to the
> carb. Upon examining the needle and seat we found the seat had a tiny
> flap of material that had torn loose which would occasionally make its
> way over the hole and completely block the flow of fuel into the bowl.
>
> However - don't worry about the carb until you confirm positive delivery
> of fuel.
>
> --Jim "saving the lives of Onans one unit at a time" Miller
> 1977 Eleganza II
> 1977 Royale
> Hamilton, OH
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
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Allen, TX
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| Re: [GMCnet] Generator stopping when it should not [message #261206 is a reply to message #261205] |
Sun, 07 September 2014 16:09 |
k2gkk
Messages: 4452
Registered: November 2009
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Assuming you have a "standard" GMC-built coach and fuel system, do you have AT LEAST 1/4 filled main fuel tank? Onans need to have that much in tank to be able to run. Since GMC tanks seek the same level in each, you really may need to be at 1/2 full to run. Perhaps the fuel line connecting the two tanks is partially blocked and when the main drops below operating level, the aux tank is slow to replenish the main? Just WAGs (Wild Ass Guesses) here.
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> From: neil@lincnetwork.com
> To: gmclist@temp.gmcnet.org
> Date: Sun, 7 Sep 2014 21:01:43 +0000
> Subject: Re: [GMCnet] Generator stopping when it should not
>
> I have by passed the inline filter and same result which it died 30
> minutes of use. Purrs like a kitten when running but dies. Pulled the
> fuel line and it was dry going into the fuel pump.
>
> I have not tried an external tank. I was thinking of picking up a 6 gal
> boat tank.
>
> I will try the bubbles test this week.
>
> Thanks everyoneŠ.I¹ll report back after the two tests.
>
> Neil
>
> On 9/7/14, 2:57 PM, "Jim Miller" wrote:
>
>> Have you tried temporarily bypassing the inline filter? Or perhaps
>> installed a new one?
>>
>> Have you tried running the Onan via a gas can instead of the vehicle
>> tank? If so does the stalling problem recur?
>>
>> Have you tried Matt's suggesting of directing the pump's output into a
>> can to ensure you get good flow with no bubbles?
>>
>> These first steps will help you find - or let you rule out - a fuel
>> delivery problem.
>>
>> If delivery of the raw fuel is OK then you can start looking at the carb
>> - we worked on one here at the compound that would run for a bit and then
>> fall over - each time it died we found it had a dry bowl. We ruled out
>> fuel delivery using the steps above and thus narrowed it down to the
>> carb. Upon examining the needle and seat we found the seat had a tiny
>> flap of material that had torn loose which would occasionally make its
>> way over the hole and completely block the flow of fuel into the bowl.
>>
>> However - don't worry about the carb until you confirm positive delivery
>> of fuel.
>>
>> --Jim "saving the lives of Onans one unit at a time" Miller
>> 1977 Eleganza II
>> 1977 Royale
>> Hamilton, OH
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
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| Re: [GMCnet] Generator stopping when it should not [message #261208 is a reply to message #261105] |
Sun, 07 September 2014 16:27 |
midlf
Messages: 2212
Registered: July 2007
Location: SE Wisc. (Palmyra)
Karma: 1
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I'm not sure what you mean by "bit newer Onan" Model number, ect? The OEM power drawer fuel pump has a filter screen in the bottom of it. The OEM power drawer carb also has a filter screen in the bottom of the carb.
Steve Southworth
1974 Glacier TZE064V100150 (for workin on)
1975 Transmode TZE365V100394 (parts & spares)
Palmyra WI
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| Re: [GMCnet] Generator stopping when it should not [message #261258 is a reply to message #261210] |
Sun, 07 September 2014 22:40 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Neville,
Sorry Mate but when I looked at the spec sheet you provided your Onan you have is WAY different from the ones in our GMC's.
I think you may be barking up the wrong tree trying to get help here unless someone else has one.
Regards,
Rob M.
The Pedantic Mechanic
USAussie - Downunder
USA '75 Avion - Double Trouble TZE365V100426
AUS '75 Avion - The Blue Streak TZE365V100428
-----Original Message-----
From: Neil Fonville
I have a Genset 6500 vintage 1997 or so. Here is the spec sheet: http://campkahler.com/files/onan/emerald6500.pdf
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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