| Fuel pump for Onan 6kw [message #255240] |
Sun, 13 July 2014 15:27  |
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RF_Burns
Messages: 2277
Registered: June 2008
Location: S. Ontario, Canada
Karma: 3
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Seems my fuel pump on the Onan died over the winter. I have a Facet 40103 pump new in box sitting here. I'm sure I read the Onan wants very low fuel pressure, but I can't seem to find that info.
I found where this 40103 pump is rated at 7-10psi. Is this too high?
thanks
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.
1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that
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| Re: Fuel pump for Onan 6kw [message #255242 is a reply to message #255240] |
Sun, 13 July 2014 15:47  |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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I believe the ONAN wants a 3 PSI pump. You could try that pump but I'm afraid it will over power the needle valve and flood the engine. It might even cause a leak from the carb to the outside and cause a fire hazard. I would not do it.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: Fuel pump for Onan 6kw [message #255248 is a reply to message #255245] |
Sun, 13 July 2014 16:37 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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RF_Burns wrote on Sun, 13 July 2014 16:16Thanks guys, I'll look for a lower pressure pump.
I also noticed the ignition coil was connected backwards ( power to neg and points to positive terminal). Not sure if it will make any difference, it was running fine. But the polarity was marked on there for a purpose.
I'm running that negative / positive thing through my mind. Since neither the primary or secondary of that coil have any reference to ground, I can not come up with a reason why it would make any difference.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: Fuel pump for Onan 6kw [message #255263 is a reply to message #255255] |
Sun, 13 July 2014 19:40 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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I was thinking about the secondary (high voltage) side firing in the reverse direction but they already have that happening to one plug anyway. The two plugs (on the secondary side) are wired in series with the engine ground being the connection between the two plugs. I just can not come up with a scenario where the primary side being reversed would cause a problem.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: Fuel pump for Onan 6kw [message #255300 is a reply to message #255263] |
Sun, 13 July 2014 23:59 |
cbryan
Messages: 451
Registered: May 2012
Location: Ennis, Texas
Karma: 3
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Ken Burton wrote on Sun, 13 July 2014 19:40I was thinking about the secondary (high voltage) side firing in the reverse direction but they already have that happening to one plug anyway. The two plugs (on the secondary side) are wired in series with the engine ground being the connection between the two plugs. I just can not come up with a scenario where the primary side being reversed would cause a problem.
Was getting ready to disagree, but went to a Harley Davidson site where I think the coils are the same, and it appears that in that application as you say, it makes no difference. I did find this about single ended coils at MGAGURU.com.
The MGA With An Attitude
MGAguru.com MGAguru.com
IGNITION COIL POLARITY - IG-104
There is some misconception about ignition coil polarity and how important it may be (or not). For most people it is only a matter of lack of knowledge, perhaps followed by getting some bad information. How the coil works (with points and condenser) to create a high voltage spark is covered in another article. This article is a discussion about electrical polarity of the coil and spark plugs.
The ignition coil is essentially a low voltage to high voltage transformer with about 100 to 1 ratio of windings and voltage. The coil case is not grounded, and both primary and secondary windings inside are "floating" or isolated from the case. The only thing the windings have in common is one end connected to the same primary terminal, and it really doesn't matter much which one. Being a transformer it must have pulsating or alternating current to work. Initial pulsating is done by connecting and disconnecting the primary circuit ground connection. Alternating current then comes into the function in a big way by electrical "ringing" in the condenser at very high frequency. A transformer is not affected by polarity, since it is an alternating current device, so it matters not to the transformer what the input or output polarity may be. Any polarity on the primary side and any polarity on high tension side will produce the same quality of spark.
Why then do we worry about coil polarity? Because the spark plugs do care which way the electrons are flowing in the high tension circuit. The spark plug has a thermally insulated center electrode (surrounded by ceramic). With engine running the center electrode runs substantially hotter than the exposed end electrode. Design of the ceramic insulator determines how hot the center electrode will run, leading to the designation of hotter or colder spark plugs. As electrons go, they love to jump away from a hot surface and fly toward a colder surface, so it is easier to drive them from hot to cold rather than from cold to hot. End result is a difference of 15 to 30 percent in voltage required to make spark "initially" jump the gap on the plug depending on which way it is going. So the spark plug prefers to see a voltage potential that is negative on the center electrode and positive on the end electrode for the very first hop of the spark. Oddly enough, this has nothing to do with polarity of the vehicle electrical system, but it is influenced by the common connection inside the ignition coil.
End quote. But as you say, the polarity of the two plugs which fire simultaneously (giving a waste spark on one cylinder), will be opposite no matter which way you wire the primary of the coil. It remains to be explained that given all these facts, why the manufacturer bothered to put positive and negative markings on these coils.
Carey
Carey from Ennis, Texas
78 Royale, 500 Cadillac, Rance Baxter EFI.
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| Re: Fuel pump for Onan 6kw [message #255306 is a reply to message #255300] |
Mon, 14 July 2014 03:11 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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My logic in a wasted spark system is that while one plug is seeing a negative rise in voltage the opposite one is seeing a positive voltage rise. So as most we might be changing which plug is seeing negative while the other one is seeing positive.
I have seen recommendations that the two spark plugs be swapped occasionally to reduce or balance the erosion of the electrodes. I have never bothered to do it.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] Fuel pump for Onan 6kw [message #255307 is a reply to message #255248] |
Mon, 14 July 2014 03:54 |
Mr ERFisher
Messages: 7117
Registered: August 2005
Karma: 2
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I think it has to do with the ringing of the coil. The negative is the
bottom of the primary and secondary coils, the secondary rings to a higher
voltage when the points open with the cap a part of the circuit (one end
grounded)
someone will find a desc.on google :>)
erf
On Sun, Jul 13, 2014 at 2:37 PM, Ken Burton wrote:
> RF_Burns wrote on Sun, 13 July 2014 16:16
>> Thanks guys, I'll look for a lower pressure pump.
>>
>> I also noticed the ignition coil was connected backwards ( power to neg
> and points to positive terminal). Not sure if it will make any difference,
>> it was running fine. But the polarity was marked on there for a purpose.
>
>
>
> I'm running that negative / positive thing through my mind. Since neither
> the primary or secondary of that coil have any reference to ground, I can
> not come up with a reason why it would make any difference.
> --
> Ken Burton - N9KB
> 76 Palm Beach
> Hebron, Indiana
> _______________________________________________
> GMCnet mailing list
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--
Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
-------
http://gmcmotorhome.info/
Alternator Protection Cable
http://gmcmotorhome.info/APC.html
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| Re: [GMCnet] Fuel pump for Onan 6kw [message #255312 is a reply to message #255300] |
Mon, 14 July 2014 08:59 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Carey,
You are correct, Harley-Davidson's used a waste spark just like the Onan, you can buy a direct replacement coil here:
http://www.jpcycles.com/product/3000140
I was wrong, that sucker is CHROME PLATED!
Regards,
Rob M.
The Pedantic Mechanic
USAussie - Downunder
USA '75 Avion - Double Trouble TZE365V100426
AUS '75 Avion - The Blue Streak TZE365V100428
-----Original Message-----
From: Carey Bryan
Was getting ready to disagree, but went to a Harley Davidson site where I think the coils are the same, and it appears that in that
application as you say, it makes no difference. I did find this about single ended coils at MGAGURU.com.
Carey
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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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| Re: [GMCnet] Fuel pump for Onan 6kw [message #255315 is a reply to message #255312] |
Mon, 14 July 2014 09:25 |
midlf
Messages: 2212
Registered: July 2007
Location: SE Wisc. (Palmyra)
Karma: 1
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USAussie wrote on Mon, 14 July 2014 08:59Carey,
You are correct, Harley-Davidson's used a waste spark just like the Onan, you can buy a direct replacement coil here:
http://www.jpcycles.com/product/3000140
I was wrong, that sucker is CHROME PLATED!
Regards,
Rob M.
The Pedantic Mechanic
That also includes the wire set w/ connectors for both ends. Reviews note the tendancy to break the spot welds on the bracket. That should not be a problem on the Onan as the vibration duty is a lot less than a Harley. <no grin, serious statement>
Steve Southworth
1974 Glacier TZE064V100150 (for workin on)
1975 Transmode TZE365V100394 (parts & spares)
Palmyra WI
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| Re: [GMCnet] Fuel pump for Onan 6kw [message #255320 is a reply to message #255315] |
Mon, 14 July 2014 10:15 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Senior Member |
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Steve,
I'll bet a lot of these guys don't know the nickname "Milwaukee Vibrator."
Regards,
Rob M.
-----Original Message-----
From: Steve Southworth
That also includes the wire set w/ connectors for both ends. Reviews note the tendancy to break the spot welds on the bracket.
That should not be a problem on the Onan as the vibration duty is a lot less than a Harley.
--
Steve
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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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