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| choke on genny question [message #132023] |
Sat, 25 June 2011 21:24  |
chasingsummer
Messages: 434
Registered: May 2011
Location: asheboro, nc
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75 coach with 6k generator. coil gets the 12 volts but arm does not move, i think i saw mwntioned on line somewhere about and adjustment, as if coil could be rotated? once warm genny seems to run good so i dont really want to buy an electric choke if i can help it
also somewhat related, i saw a listing somewhere that had a small schematic related to priming the carb for remote operation, it involved adding another switch to remote panel, fused, then diode to stop reverse power, it received 12vdc from panel and somehow i guess ran the fule pump momentaryily to ease in start up. does this really help? where on genny is this 12 vdc connected?
thanks bgk
brian
asheboro, nc
75 eleganza, 74 build
119k miles and counting,
DOG HOUSE
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| Re: choke on genny question [message #132024 is a reply to message #132023] |
Sat, 25 June 2011 21:28  |
Dennis S
Messages: 3046
Registered: November 2005
Karma: 2
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| chasingsummer wrote on Sat, 25 June 2011 21:24 |
75 coach with 6k generator. coil gets the 12 volts but arm does not move, i think i saw mwntioned on line somewhere about and adjustment, as if coil could be rotated? once warm genny seems to run good so i dont really want to buy an electric choke if i can help it
also somewhat related, i saw a listing somewhere that had a small schematic related to priming the carb for remote operation, it involved adding another switch to remote panel, fused, then diode to stop reverse power, it received 12vdc from panel and somehow i guess ran the fule pump momentaryily to ease in start up. does this really help? where on genny is this 12 vdc connected?
thanks bgk
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bgk,
You may want to spend some time looking at Gene's site .. lots of links to Onan articles...
http://gmcmotorhome.info/list.html#GEN
He has a link to the prime switch -- yes, it works..
Some discussion on the choke. You may want to check the electrical connection on the choke -- try hitting it with known 12v to see if it works.
Dennis
Dennis S
73 Painted Desert 230
Memphis TN Metro
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| Re: choke on genny question [message #132057 is a reply to message #132023] |
Sun, 26 June 2011 02:23 |
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mike miller
Messages: 3576
Registered: February 2004
Location: Hillsboro, Oregon
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| chasingsummer wrote on Sat, 25 June 2011 19:24 |
75 coach with 6k generator. coil gets the 12 volts but arm does not move, ...
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1st I would suspect a bad ground at the choke. The normal path for the ground is through the exhaust manifold. To test, ground the choke with some jumper cables. I have seen many Onans with a wire added to ground the choke. The wire normally melts and/or burns the insulation near the choke... but it is ground... no biggie.
If jumper cables grounding your choke do not help, you might need to dig a bit deeper.
For info:
The Onan choke has two methods of operation. Both parts have to work for the generator to start reliably.
One part of the choke is thermally activated. That is why it is mounted on the exhaust. It closes the choke about half way. As the manifold warms up, the choke fully opens. It also has an electric part, that is activated anytime the starter is engaged. This electric choke also closes the choke about half way, in addition with the thermal choke. This half choke is applied even if the motor is still hot. This works as the engine is always started at full open throttle -- Due to governor action.
So it the choke is cold and before the starter is engaged it is already half closed. Press the start button, and the choke closes all the way. When the starter is disengaged, the choke returns to half... Until the motor warms up.
Mike Miller -- Hillsboro, OR -- on the Black list
(#2)`78 23' Birchaven Rear Bath -- (#3)`77 23' Birchaven Side Bath
More Sidekicks than GMC's and a late model Malibu called 'Boo'
http://m000035.blogspot.com
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| Re: choke on genny question [message #132087 is a reply to message #132023] |
Sun, 26 June 2011 11:20 |
chasingsummer
Messages: 434
Registered: May 2011
Location: asheboro, nc
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i see my choke working as it warms up, the angle of the arm changes,
i hit the coil with 12vdc from the battery and nothing, and this was with it disconnected from carb, i did not think to try a different ground, my hesitation to remove it due to the rusted up mounted bolts , i hate breaking things and adding to my list of things to fix.
i do plan on adding the gas booster set up. makes a lot of since
brian
asheboro, nc
75 eleganza, 74 build
119k miles and counting,
DOG HOUSE
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| Re: choke on genny question [message #132088 is a reply to message #132087] |
Sun, 26 June 2011 11:26 |
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mike miller
Messages: 3576
Registered: February 2004
Location: Hillsboro, Oregon
Karma: 0
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| chasingsummer wrote on Sun, 26 June 2011 09:20 |
...
i do plan on adding the gas booster set up. makes a lot of since
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gas booster?
Mike Miller -- Hillsboro, OR -- on the Black list
(#2)`78 23' Birchaven Rear Bath -- (#3)`77 23' Birchaven Side Bath
More Sidekicks than GMC's and a late model Malibu called 'Boo'
http://m000035.blogspot.com
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| Re: [GMCnet] choke on genny question [message #132090 is a reply to message #132087] |
Sun, 26 June 2011 11:30 |
emerystora
Messages: 4442
Registered: January 2004
Karma: 13
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On Jun 26, 2011, at 10:20 AM, brian wrote:
>
>
> i see my choke working as it warms up, the angle of the arm changes,
> i hit the coil with 12vdc from the battery and nothing, and this was with it disconnected from carb, i did not think to try a different ground, my hesitation to remove it due to the rusted up mounted bolts , i hate breaking things and adding to my list of things to fix.
> i do plan on adding the gas booster set up. makes a lot of since
>
Hitting the choke with 12v is not going to pull the choke on. The coil in the choke is there to hold the choke in the on position until the bimetallic strip pulls it away from the hold position.
No wire goes to the bimetallic strip. A bimetallic strip is a
mechanical device which has two layers of metal that expand at
different amounts when heat is applied. That causes the strip to bend.
If you look at a typical house thermostat for a furnace you will see a
coil. This is also a bimetallic strip which coils and uncoils with
room temperature.
So the electromagnet holds the choke closed and as the Onan starts to
warm up the exhaust heat transfers some heat to the choke housing and
the bimetallic strip starts to heat up and expand which pulls the
choke metal plate away from the electromagnet and the choke begins to
open. When totally warmed up the choke is fully opened.
The choke gets it's 12 volts from the start relay on the control
board. It doesn't get any power after that when the Onan is
running.
Years ago when my choke wasn't operating right I saw the rusty bolts that hold it to the manifold and right away assumed that was getting a poor ground. So, I cleaned a spot on the side of the choke and soldered a length of wire to the choke housing and put a ring terminal on the other end of the wire and attached it to the Onan support frame where it wasn't getting heat as the manifold does. I have never had a problem with the choke since.
Emery Stora
77 Kingsley
Santa Fe, NM
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| Re: [GMCnet] choke on genny question [message #132093 is a reply to message #132087] |
Sun, 26 June 2011 12:26 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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I am not sure as to how I can advise you, so I will ask you to contact
the best person:Duane Simmons
(714)633-4731
Advise him that the Kan of Tomatoes reffed you to him.
Call him today.
For you info the chock is not available new. We have some used ones here.
On Sun, Jun 26, 2011 at 9:20 AM, brian <chasingsummer@triad.rr.com> wrote:
>
>
> i see my choke working as it warms up, the angle of the arm changes,
> i hit the coil with 12vdc from the battery and nothing, and this was with it disconnected from carb, i did not think to try a different ground, my hesitation to remove it due to the rusted up mounted bolts , i hate breaking things and adding to my list of things to fix.
> i do plan on adding the gas booster set up. makes a lot of since
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
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>
--
Jim Kanomata
Applied/GMC, Fremont,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
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Jim Kanomata
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| Re: choke on genny question [message #132370 is a reply to message #132023] |
Mon, 27 June 2011 20:55 |
chasingsummer
Messages: 434
Registered: May 2011
Location: asheboro, nc
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i know or i think i know my bio metal piece works, as onan runs and gets warmer the arm on the choke slowly works itself counter clock wise, i assume that it is doing correctly,
i know i get the 12 volts when starting based on meter reading,
shouldnt this 12v pull choke completely clock wise and hold while cranking?
i installed the fuel booster set up, purple off run stop switch is where i obtained my 12 vdc, thru fuse, then push switch , then diode then to hot side of my run meter, which was label as hot side. hold switch and pump pumps. but after dark so no running of genny as a curtisity to neighbor. i hope to add ground to coil tomorrow after work and confurm sometyhing with it.
brian
asheboro, nc
75 eleganza, 74 build
119k miles and counting,
DOG HOUSE
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| Re: choke on genny question [message #132408 is a reply to message #132370] |
Tue, 28 June 2011 02:44 |
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mike miller
Messages: 3576
Registered: February 2004
Location: Hillsboro, Oregon
Karma: 0
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| chasingsummer wrote on Mon, 27 June 2011 18:55 |
...
i know i get the 12 volts when starting based on meter reading,
shouldnt this 12v pull choke completely clock wise and hold while cranking?
i installed the fuel booster set up, purple off run stop switch is where i obtained my 12 vdc, thru fuse, then push switch , then diode then to hot side of my run meter, which was label as hot side. hold switch and pump pumps. ...
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"fuel booster" ... Most of us call that a "PRIME" switch. As it primes the carb float bowl. But you can call it what you want... we'll just scratch our heads! 
2 things, it also supplies power to the ignition system... by passing the safety circuits on the control board. And if you accidentally press the prime while stopping the generator, you'll blow the fuse as the stop switch grounds the 12v on the hot side of the run meter.
The 12v at the choke tells me you have a bad ground or a bad choke. I have disassembled and repaired a choke with some success. I have also seen one that got "sticky." If not used you had to wiggle the choke arm a bit and it would work fine.... unless allowed to sit, unused, for a month or so.
YES... When cold, the 12v choke signal should close the choke. BUT, when warm it might not. This is due to your "bio metal piece" working as it should.
Mike Miller -- Hillsboro, OR -- on the Black list
(#2)`78 23' Birchaven Rear Bath -- (#3)`77 23' Birchaven Side Bath
More Sidekicks than GMC's and a late model Malibu called 'Boo'
http://m000035.blogspot.com
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