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[GMCnet] lack of choke on carb [message #307970] Wed, 28 September 2016 16:41 Go to next message
Burt and Faye curtis is currently offline  Burt and Faye curtis   United States
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Registered: June 2012
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Senior Member
Last year when the rebuilt Pattersen carb was installed on my coach, a
choke wasn't installed as the mechanic felt it was dropping down the idle
just fine. Bert had connected up a manual choke on the first one. Now a
friend insists that I need a choke or it will never run right and will
always be idling too high and killing the fuel mileage. So, if it is in
fact dropping the idle after a while, do I really need the choke? Coach
starts up just fine as it is.

Thanks again in advance,

Fay Curtis
'76 Glenbrook
Kneeland, CA
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Re: [GMCnet] lack of choke on carb [message #307974 is a reply to message #307970] Wed, 28 September 2016 18:31 Go to previous messageGo to next message
Loffen is currently offline  Loffen   Norway
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Does it idle to high now ? if so get it up to operating temperature and set the idle to 650 rpm or so in drive, if it is hard to start when cold after you have adjusted the idle it should not take more than a light foot on the accelerator for a couple of minutes until the engine get a little hot.
So to your question, do you need the choke in CA ? nah not really, it will not do anything after the engine reaches it operating temperature, in colder climates I think that you will need it just as it will make everything easier for you when it comes to start up and driving the first couple of miles


1973 23' # 1848 Sky Blue Glacier called Baby Blue and a 1973 26'-3 # 1460 Parrot green Seqouia Known as the Big Green, And sold my 1973 26'-2 # 581 White Canyon lands under the name Dobbelt trøbbel in Norway
Re: [GMCnet] lack of choke on carb [message #307982 is a reply to message #307974] Wed, 28 September 2016 19:32 Go to previous messageGo to next message
Burt and Faye curtis is currently offline  Burt and Faye curtis   United States
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Registered: June 2012
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Senior Member
Espen,

Thanks for your help. Felt that it was probably good as I trust the guy
that installed it, but now I have to get the other fellow to keep his paws
off of it!

Fay

On Wed, Sep 28, 2016 at 4:31 PM, Espen Heitmann wrote:

> Does it idle to high now ? if so get it up to operating temperature and
> set the idle to 650 rpm or so in drive, if it is hard to start when cold
> after
> you have adjusted the idle it should not take more than a light foot on
> the accelerator for a couple of minutes until the engine get a little hot.
> So to your question, do you need the choke in CA ? nah not really, it will
> not do anything after the engine reaches it operating temperature, in
> colder climates I think that you will need it just as it will make
> everything easier for you when it comes to start up and driving the first
> couple of
> miles
> --
> 1973 26'-3 # 1460 Parrot green Seqouia Known as the Big Mean Green Machine,
> And just sold my 1973 26'-2 # 581 White Canyon lands under the name
> Dobbelt trøbbel
> in Norway
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
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Re: [GMCnet] lack of choke on carb [message #307994 is a reply to message #307974] Wed, 28 September 2016 23:32 Go to previous messageGo to next message
jimk is currently offline  jimk   United States
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Registered: July 2006
Location: Belmont, CA
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Senior Member
You do need the choke to start and be able to drive off in a minute.
I'm i Northern CA, and even in Southern CA it is never warm enough to not
need a choke unless the carb is running extra rich.
We do work on several a month, so I know for sure on this.

On Wed, Sep 28, 2016 at 4:31 PM, Espen Heitmann wrote:

> Does it idle to high now ? if so get it up to operating temperature and
> set the idle to 650 rpm or so in drive, if it is hard to start when cold
> after
> you have adjusted the idle it should not take more than a light foot on
> the accelerator for a couple of minutes until the engine get a little hot.
> So to your question, do you need the choke in CA ? nah not really, it will
> not do anything after the engine reaches it operating temperature, in
> colder climates I think that you will need it just as it will make
> everything easier for you when it comes to start up and driving the first
> couple of
> miles
> --
> 1973 26'-3 # 1460 Parrot green Seqouia Known as the Big Mean Green Machine,
> And just sold my 1973 26'-2 # 581 White Canyon lands under the name
> Dobbelt trøbbel
> in Norway
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>



--
Jim Kanomata
Applied/GMC, Fremont,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
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Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
Re: [GMCnet] lack of choke on carb [message #308017 is a reply to message #307970] Thu, 29 September 2016 15:12 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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Burt and Faye curtis wrote on Wed, 28 September 2016 17:41
Last year when the rebuilt Pattersen carb was installed on my coach, a choke wasn't installed as the mechanic felt it was dropping down the idle just fine. Bert had connected up a manual choke on the first one. Now a friend insists that I need a choke or it will never run right and will always be idling too high and killing the fuel mileage. So, if it is in fact dropping the idle after a while, do I really need the choke? Coach starts up just fine as it is.

Thanks again in advance,

Fay Curtis

Fay,

I have to wonder what is going on here.
When you say no choke was installed?
Do you mean no choke plates? (The double butterfly that is right at the top of the carburetor?)
Or
Do you mean no thermal choke operator? (The device that opens and closes the choke as you might do with a manual cable.)

If it is the former, then you will indeed have a hard time starting cold and there is a lot else that will be difficult, but as you say this is not an issue, lets go on.

If the thermal operator heater is what is missing, then I am going to assume that you mean the connection to the manifold heater (often referred to as a cross-over) has not been installed. Without these parts, the choke will probably function as intended but the pull off time will be longer than it should. This will cause the engine to stay at a high idle longer than desired. But, again, you say that this is not an issue. If the parts are available, this is no big deal to install. If they are not, it is even simpler because you can change it to an electric version for a small price.

If the situation is causing you some concern, you might have someone check into it, but again, it sounds as though it is not. Unless you plan to go someplace that is much colder than you are accustom to, just enjoy the coach.

There are lots of carburetor fueled engines out in the world with no choke system at all. The operators just have to be aware of the situation.

Matt - the engine lab refugee


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] lack of choke on carb [message #308028 is a reply to message #307970] Thu, 29 September 2016 19:14 Go to previous messageGo to next message
pjburt is currently offline  pjburt   United States
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Registered: February 2016
Location: Fresno, California
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Senior Member
Burt and Faye curtis wrote on Wed, 28 September 2016 14:41
Last year when the rebuilt Pattersen carb was installed on my coach, a
choke wasn't installed as the mechanic felt it was dropping down the idle
just fine.

If on cold start there is a high idle and it drops to a lower idle after a short warmup, it sounds like there is something activating the high idle cam. It is independent from the throttle.
Quote:

Bert had connected up a manual choke on the first one. Now a
friend insists that I need a choke or it will never run right and will
always be idling too high and killing the fuel mileage.

What is your warmed idle RPM.
Quote:
So, if it is in fact dropping the idle after a while, do I really need the choke? Coach starts up just fine as it is.

I believe you do have a choke. It may not be hooked up but you are in Cal, so... You are just fine as you are. If it becomes a problem in the winter, just give it a little more gas to start,if needed, and let it idle a little longer at warmup. The idle cam will drop as it warms up when you blip the accelerator, if you don't get crazy revving it up.[quote]


Thanks again in advance,

Fay Curtis
'76 Glenbrook
Kneeland, CA
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[quote]


Jerry Burt Fresno, CA.
73 Gmc 26' Canyon Lands
Members: FMCA - GMCMI - GMCWS
A truly happy person is one who can enjoy the scenery on a detour.
Re: [GMCnet] lack of choke on carb [message #308053 is a reply to message #308028] Fri, 30 September 2016 12:39 Go to previous messageGo to next message
Jon payne is currently offline  Jon payne   United States
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Registered: May 2008
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Senior Member
I really can't imagine why one would not want an operating choke. With outside temps warm or cold the engine starts much better with a choke and improves driveability when you first start, just like JimK says. So I say get the choke fixed as it is there for a reason.

Jon


Jon Payne
76 Palm Beach
Westfield,IN
Re: [GMCnet] lack of choke on carb [message #308054 is a reply to message #308053] Fri, 30 September 2016 13:02 Go to previous message
James Hupy is currently offline  James Hupy   United States
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Registered: May 2010
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Senior Member
I talked on the phone with Faye yesterday. She has an adjustment problem,
not a part missing. She has it under control.
Jim Hupy
Salem, Or
78 GMC ROYALE 403
On Sep 30, 2016 10:40 AM, "Jon Payne" wrote:

> I really can't imagine why one would not want an operating choke. With
> outside temps warm or cold the engine starts much better with a choke and
> improves driveability when you first start, just like JimK says. So I say
> get the choke fixed as it is there for a reason.
>
> Jon
> --
> Jon Payne
> 76 Palm Beach
> Westfield,IN
>
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