Home » Public Forums » GMCnet » It was not a cracked intake- it was the carb. now what?
| It was not a cracked intake- it was the carb. now what? [message #369243] |
Thu, 24 March 2022 18:15  |
hertfordnc
Messages: 1164
Registered: September 2009
Location: East NC
Karma: 0
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Senior Member |
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This coach had been fully rebuilt and then parked for seven years when i got it.
This made it hard to troubleshoot. It would run OK and then bog down. So of course we looked at fuel lines, filters, old gas etc.
Got all that sorted still no change. Chased vac leaks etc. No change.
Then someone suggested a cracked intake- that fit the symptoms perfectly. The issue would get worse as the engine warmed up but also, the severity would get worse over time. So it made perfect sense that a crack would open more as the engine wormed and get bigger over time.
I scored a good intake and commenced to changing it. And when it was all back together there is NO CHANGEit still does not run right.
So maybe the carb? The Revcon is sitting there, has not been run in over a year. The original Toronado Carb has NEVER been rebuilt, but i swap it out and the GMC runs PERFECTLY!
Ok, that was a long and winding road. Whatever is going on is happening in the carb ONLY.
Here's the symptoms-(before i swapped the carb) engine starts pretty easily, takes off smoothly and accelerates into second gear and then has no more power. If I give it more gas is bogs down like it's gonna stall.
This gets worse the longer i drive it (lately not more than a couple miles)
This carb was freshly rebuilt for the Coop in 2013. it went 1000 miles and did not move again so I'm not inclined to tear in all apart, it's not like parts are worn or thousands of gallons of fuel have run through it.
What Say the Brain Trust ?
Dave & Ellen Silva
Hertford, NC
76 Birchaven, 1-ton and other stuff
Currently planning the Great american Road Trip Summer 2021
It's gonna take a lot of Adderall to get this thing right.
[Updated on: Fri, 25 March 2022 08:47] Report message to a moderator |
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| [GMCnet] Re: It was not a cracked intake- it was the carb. now what? [message #369244 is a reply to message #369243] |
Thu, 24 March 2022 18:20  |
Len Novak
Messages: 676
Registered: February 2004
Location: Las Vegas, NV
Karma: -3
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Senior Member |
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Just for grins look for a crack at the base of the carb. Been there,
done that. Took forever to find that.
Len Novak
On 3/24/2022 4:15 PM, dave silva wrote:
> This coach had been fully rebuilt and then parked for seven years when i got it.
>
> This made it hard to troubleshoot. It would run OK and then bog down. So of course we looked at fuel lines, filters, old gas etc.
>
> Got all that sorted still no change. Chased vac leaks etc. No change.
>
> Then someone suggested a cracked intake- that fit the symptoms perfectly. The issue would get worse as the engine warmed up but also, the severity
> would get worse over time. So it made perfect sense that a crack would open more as the engine wormed and get bigger over time.
>
> I scored a good intake and commenced to changing it. And when it was all back together there is NO CHANGEit still does not run right.
>
> So maybe the carb? The Revcon is sitting there, has not been run in over a year. The original Toronado Carb has NEVER been rebuilt, but i swap it
> out and the Coach runs PERFECTLY!
>
> Ok, that was a long and winding road. Whatever is going on is happening in the carb ONLY.
>
>
> Here's the symptoms- engine starts pretty easily, takes off smoothly and accelerates into second gear and then has no more power. If I give it more
> gas is bogs down like it's gonna stall.
>
> This gets worse the longer i drive it (lately not more than a couple miles)
>
> This carb was freshly rebuilt for the Coop in 2013. it went 1000 miles and did not move again so I'm not inclined to tear in all apart, it's not like
> parts are worn or thousands of gallons of fuel have run through it.
>
> What Say the Brain Trust ?
>
>
>
>
>
>
>
>
>
>
>
>
>
>
--
Len and Pat Novak 1978 GMC Kingsley The Beast II with dash lights that
work and labels you can see! Las Vegas, NV new email: B52srule@gmail.com
http://www.gmcmhphotos.com/photos/showgallery.php?cat=4375
www.bdub.net/novak/
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GMCnet mailing list
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Len and Pat Novak
1978 GMC Kingsley
The Beast II with dash lights that work and labels you can see!
Las Vegas, NV new email: B52sRule@Gmail.com
http://www.gmcmhphotos.com/photos/showgallery.php?cat=4375
www.bdub.net/novak/
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| [GMCnet] Re: It was not a cracked intake- it was the carb. now what? [message #369245 is a reply to message #369244] |
Thu, 24 March 2022 21:00 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Senior Member |
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There are two kinds of cast iron manifolds. Those that are cracked, and
those that haven't cracked yet. If the cracks are accessible from the
bottom, a hole can be drilled at each end of the crack, "V" ing out the
crack with a die grinder, then tig welding the crack with rod intended for
cast iron repair. Or, use the same prep and use bronze brazing rod. When
you finish, then block off the crossover with stainless steel plates
between the heads and manifold. Some have filled the crossover passage with
poured molten aluminum or other metals. I have not done either of these
methods, but I have practiced on a severely cracked manifold.
If the manifold is cracked through to the intake passages under the
carb, it is tough sledding to get effective welds in there.
Jim Hupy
Salem, Oregon
On Thu, Mar 24, 2022, 6:32 PM CJV wrote:
> Is there any way to satisfactorily repair a cracked manifold?
>
> CJ Vermeulen, Scribbler
>
>
> From: "Len Novak"
> To: "dave silva" , "gmclist"
> Sent: Thursday, March 24, 2022 6:20:48 PM
> Subject: [GMCnet] Re: It was not a cracked intake- it was the carb. now
> what?
>
> Just for grins look for a crack at the base of the carb. Been there,
> done that. Took forever to find that.
>
>
> Len Novak
>
>
>
> On 3/24/2022 4:15 PM, dave silva wrote:
>
>
> This coach had been fully rebuilt and then parked for seven years when i
> got it.
>
> This made it hard to troubleshoot. It would run OK and then bog down. So
> of course we looked at fuel lines, filters, old gas etc.
>
> Got all that sorted still no change. Chased vac leaks etc. No change.
>
> Then someone suggested a cracked intake- that fit the symptoms perfectly.
> The issue would get worse as the engine warmed up but also, the severity
> would get worse over time. So it made perfect sense that a crack would
> open more as the engine wormed and get bigger over time.
>
> I scored a good intake and commenced to changing it. And when it was all
> back together there is NO CHANGEit still does not run right.
>
> So maybe the carb? The Revcon is sitting there, has not been run in over a
> year. The original Toronado Carb has NEVER been rebuilt, but i swap it
> out and the Coach runs PERFECTLY!
>
> Ok, that was a long and winding road. Whatever is going on is happening in
> the carb ONLY.
>
>
> Here's the symptoms- engine starts pretty easily, takes off smoothly and
> accelerates into second gear and then has no more power. If I give it more
> gas is bogs down like it's gonna stall.
>
> This gets worse the longer i drive it (lately not more than a couple
> miles)
>
> This carb was freshly rebuilt for the Coop in 2013. it went 1000 miles and
> did not move again so I'm not inclined to tear in all apart, it's not like
> parts are worn or thousands of gallons of fuel have run through it.
>
> What Say the Brain Trust ?
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
> --
> Len and Pat Novak 1978 GMC Kingsley The Beast II with dash lights that
> work and labels you can see! Las Vegas, NV new email: B52srule@gmail.com
> http://www.gmcmhphotos.com/photos/showgallery.php?cat=4375
> www.bdub.net/novak/
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
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| [GMCnet] Re: It was not a cracked intake- it was the carb. now what? [message #369246 is a reply to message #369244] |
Thu, 24 March 2022 20:31 |
hertfordnc
Messages: 1164
Registered: September 2009
Location: East NC
Karma: 0
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Senior Member |
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Is there any way to satisfactorily repair a cracked manifold?
CJ Vermeulen, Scribbler
From: "Len Novak"
To: "dave silva" , "gmclist"
Sent: Thursday, March 24, 2022 6:20:48 PM
Subject: [GMCnet] Re: It was not a cracked intake- it was the carb. now what?
Just for grins look for a crack at the base of the carb. Been there,
done that. Took forever to find that.
Len Novak
On 3/24/2022 4:15 PM, dave silva wrote:
This coach had been fully rebuilt and then parked for seven years when i got it.
This made it hard to troubleshoot. It would run OK and then bog down. So of course we looked at fuel lines, filters, old gas etc.
Got all that sorted still no change. Chased vac leaks etc. No change.
Then someone suggested a cracked intake- that fit the symptoms perfectly. The issue would get worse as the engine warmed up but also, the severity
would get worse over time. So it made perfect sense that a crack would open more as the engine wormed and get bigger over time.
I scored a good intake and commenced to changing it. And when it was all back together there is NO CHANGEit still does not run right.
So maybe the carb? The Revcon is sitting there, has not been run in over a year. The original Toronado Carb has NEVER been rebuilt, but i swap it
out and the Coach runs PERFECTLY!
Ok, that was a long and winding road. Whatever is going on is happening in the carb ONLY.
Here's the symptoms- engine starts pretty easily, takes off smoothly and accelerates into second gear and then has no more power. If I give it more
gas is bogs down like it's gonna stall.
This gets worse the longer i drive it (lately not more than a couple miles)
This carb was freshly rebuilt for the Coop in 2013. it went 1000 miles and did not move again so I'm not inclined to tear in all apart, it's not like
parts are worn or thousands of gallons of fuel have run through it.
What Say the Brain Trust ?
--
Len and Pat Novak 1978 GMC Kingsley The Beast II with dash lights that
work and labels you can see! Las Vegas, NV new email: B52srule@gmail.com
http://www.gmcmhphotos.com/photos/showgallery.php?cat=4375
www.bdub.net/novak/
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GMCnet mailing list
Unsubscribe or Change List Options:
_______________________________________________
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Unsubscribe or Change List Options:
Dave & Ellen Silva
Hertford, NC
76 Birchaven, 1-ton and other stuff
Currently planning the Great american Road Trip Summer 2021
It's gonna take a lot of Adderall to get this thing right.
|
|
|
|
| [GMCnet] Re: It was not a cracked intake- it was the carb. now what? [message #369247 is a reply to message #369245] |
Thu, 24 March 2022 21:54 |
CJV
Messages: 49
Registered: December 2021
Karma: 1
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Member |
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Thank you....great info....
CJ Vermeulen, Scribbler
From: "jamesh1296"
To: "gmclist"
Sent: Thursday, March 24, 2022 9:00:28 PM
Subject: [GMCnet] Re: It was not a cracked intake- it was the carb. now what?
There are two kinds of cast iron manifolds. Those that are cracked, and
those that haven't cracked yet. If the cracks are accessible from the
bottom, a hole can be drilled at each end of the crack, "V" ing out the
crack with a die grinder, then tig welding the crack with rod intended for
cast iron repair. Or, use the same prep and use bronze brazing rod. When
you finish, then block off the crossover with stainless steel plates
between the heads and manifold. Some have filled the crossover passage with
poured molten aluminum or other metals. I have not done either of these
methods, but I have practiced on a severely cracked manifold.
If the manifold is cracked through to the intake passages under the
carb, it is tough sledding to get effective welds in there.
Jim Hupy
Salem, Oregon
On Thu, Mar 24, 2022, 6:32 PM CJV wrote:
Is there any way to satisfactorily repair a cracked manifold?
CJ Vermeulen, Scribbler
From: "Len Novak"
To: "dave silva" , "gmclist"
Sent: Thursday, March 24, 2022 6:20:48 PM
Subject: [GMCnet] Re: It was not a cracked intake- it was the carb. now
what?
Just for grins look for a crack at the base of the carb. Been there,
done that. Took forever to find that.
Len Novak
On 3/24/2022 4:15 PM, dave silva wrote:
This coach had been fully rebuilt and then parked for seven years when i
got it.
This made it hard to troubleshoot. It would run OK and then bog down. So
of course we looked at fuel lines, filters, old gas etc.
Got all that sorted still no change. Chased vac leaks etc. No change.
Then someone suggested a cracked intake- that fit the symptoms perfectly.
The issue would get worse as the engine warmed up but also, the severity
would get worse over time. So it made perfect sense that a crack would
open more as the engine wormed and get bigger over time.
I scored a good intake and commenced to changing it. And when it was all
back together there is NO CHANGEit still does not run right.
So maybe the carb? The Revcon is sitting there, has not been run in over a
year. The original Toronado Carb has NEVER been rebuilt, but i swap it
out and the Coach runs PERFECTLY!
Ok, that was a long and winding road. Whatever is going on is happening in
the carb ONLY.
Here's the symptoms- engine starts pretty easily, takes off smoothly and
accelerates into second gear and then has no more power. If I give it more
gas is bogs down like it's gonna stall.
This gets worse the longer i drive it (lately not more than a couple
miles)
This carb was freshly rebuilt for the Coop in 2013. it went 1000 miles and
did not move again so I'm not inclined to tear in all apart, it's not like
parts are worn or thousands of gallons of fuel have run through it.
What Say the Brain Trust ?
--
Len and Pat Novak 1978 GMC Kingsley The Beast II with dash lights that
work and labels you can see! Las Vegas, NV new email: B52srule@gmail.com
http://www.gmcmhphotos.com/photos/showgallery.php?cat=4375
www.bdub.net/novak/
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GMCnet mailing list
Unsubscribe or Change List Options:
_______________________________________________
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| [GMCnet] Re: It was not a cracked intake- it was the carb. now what? [message #369248 is a reply to message #369245] |
Thu, 24 March 2022 22:03 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
|
Senior Member |
|
|
Filling intake has never been a worthwhile project.
The best we seen in last few years is a Stainless Steel plate with correct
thickness gasket.
Since we provide everything, we sell the ones Dick Patterson of Springfield
supplies us.
The main cause of hot intake is poor worn blown mufflers as one side can
have high restriction causing exhaust to flow through the intake to the
other side.
Most are using car mufflers as they are less
expensive.
One should be using Truck style as they will hold up.
On Thu, Mar 24, 2022 at 7:00 PM James Hupy wrote:
> There are two kinds of cast iron manifolds. Those that are cracked, and
> those that haven't cracked yet. If the cracks are accessible from the
> bottom, a hole can be drilled at each end of the crack, "V" ing out the
> crack with a die grinder, then tig welding the crack with rod intended for
> cast iron repair. Or, use the same prep and use bronze brazing rod. When
> you finish, then block off the crossover with stainless steel plates
> between the heads and manifold. Some have filled the crossover passage with
> poured molten aluminum or other metals. I have not done either of these
> methods, but I have practiced on a severely cracked manifold.
> If the manifold is cracked through to the intake passages under the
> carb, it is tough sledding to get effective welds in there.
> Jim Hupy
> Salem, Oregon
>
> On Thu, Mar 24, 2022, 6:32 PM CJV wrote:
>
>> Is there any way to satisfactorily repair a cracked manifold?
>>
>> CJ Vermeulen, Scribbler
>>
>>
>> From: "Len Novak"
>> To: "dave silva" , "gmclist"
>> Sent: Thursday, March 24, 2022 6:20:48 PM
>> Subject: [GMCnet] Re: It was not a cracked intake- it was the carb. now
>> what?
>>
>> Just for grins look for a crack at the base of the carb. Been there,
>> done that. Took forever to find that.
>>
>>
>> Len Novak
>>
>>
>>
>> On 3/24/2022 4:15 PM, dave silva wrote:
>>
>>
>> This coach had been fully rebuilt and then parked for seven years when i
>> got it.
>>
>> This made it hard to troubleshoot. It would run OK and then bog down. So
>> of course we looked at fuel lines, filters, old gas etc.
>>
>> Got all that sorted still no change. Chased vac leaks etc. No change.
>>
>> Then someone suggested a cracked intake- that fit the symptoms perfectly.
>> The issue would get worse as the engine warmed up but also, the severity
>> would get worse over time. So it made perfect sense that a crack would
>> open more as the engine wormed and get bigger over time.
>>
>> I scored a good intake and commenced to changing it. And when it was all
>> back together there is NO CHANGEit still does not run right.
>>
>> So maybe the carb? The Revcon is sitting there, has not been run in over
> a
>> year. The original Toronado Carb has NEVER been rebuilt, but i swap it
>> out and the Coach runs PERFECTLY!
>>
>> Ok, that was a long and winding road. Whatever is going on is happening
> in
>> the carb ONLY.
>>
>>
>> Here's the symptoms- engine starts pretty easily, takes off smoothly and
>> accelerates into second gear and then has no more power. If I give it
> more
>> gas is bogs down like it's gonna stall.
>>
>> This gets worse the longer i drive it (lately not more than a couple
>> miles)
>>
>> This carb was freshly rebuilt for the Coop in 2013. it went 1000 miles
> and
>> did not move again so I'm not inclined to tear in all apart, it's not
> like
>> parts are worn or thousands of gallons of fuel have run through it.
>>
>> What Say the Brain Trust ?
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> --
>> Len and Pat Novak 1978 GMC Kingsley The Beast II with dash lights that
>> work and labels you can see! Las Vegas, NV new email: B52srule@gmail.com
>> http://www.gmcmhphotos.com/photos/showgallery.php?cat=4375
>> www.bdub.net/novak/
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
--
Jim Kanomata ASE
Applied/GMC, Newark,CA
jimk@appliedairfilters.com
http://www.gmcrvparts.com
1-800-752-7502
_______________________________________________
GMCnet mailing list
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Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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| [GMCnet] Re: It was not a cracked intake- it was the carb. now what? [message #369249 is a reply to message #369244] |
Thu, 24 March 2022 22:06 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
|
Senior Member |
|
|
One cannot use a car carb as the power valve is set for lower load.
It will run, but dump lot of fuel down the intake.
On Thu, Mar 24, 2022 at 8:03 PM Jim Kanomata wrote:
> Filling intake has never been a worthwhile project.
> The best we seen in last few years is a Stainless Steel plate with correct
> thickness gasket.
> Since we provide everything, we sell the ones Dick Patterson of
> Springfield supplies us.
> The main cause of hot intake is poor worn blown mufflers as one side can
> have high restriction causing exhaust to flow through the intake to the
> other side.
> Most are using car mufflers as they are less
> expensive.
> One should be using Truck style as they will hold up.
>
> On Thu, Mar 24, 2022 at 7:00 PM James Hupy wrote:
>
>> There are two kinds of cast iron manifolds. Those that are cracked, and
>> those that haven't cracked yet. If the cracks are accessible from the
>> bottom, a hole can be drilled at each end of the crack, "V" ing out the
>> crack with a die grinder, then tig welding the crack with rod intended for
>> cast iron repair. Or, use the same prep and use bronze brazing rod. When
>> you finish, then block off the crossover with stainless steel plates
>> between the heads and manifold. Some have filled the crossover passage
>> with
>> poured molten aluminum or other metals. I have not done either of these
>> methods, but I have practiced on a severely cracked manifold.
>> If the manifold is cracked through to the intake passages under the
>> carb, it is tough sledding to get effective welds in there.
>> Jim Hupy
>> Salem, Oregon
>>
>> On Thu, Mar 24, 2022, 6:32 PM CJV wrote:
>>
>>> Is there any way to satisfactorily repair a cracked manifold?
>>>
>>> CJ Vermeulen, Scribbler
>>>
>>>
>>> From: "Len Novak"
>>> To: "dave silva" , "gmclist"
>>> Sent: Thursday, March 24, 2022 6:20:48 PM
>>> Subject: [GMCnet] Re: It was not a cracked intake- it was the carb. now
>>> what?
>>>
>>> Just for grins look for a crack at the base of the carb. Been there,
>>> done that. Took forever to find that.
>>>
>>>
>>> Len Novak
>>>
>>>
>>>
>>> On 3/24/2022 4:15 PM, dave silva wrote:
>>>
>>>
>>> This coach had been fully rebuilt and then parked for seven years when i
>>> got it.
>>>
>>> This made it hard to troubleshoot. It would run OK and then bog down. So
>>> of course we looked at fuel lines, filters, old gas etc.
>>>
>>> Got all that sorted still no change. Chased vac leaks etc. No change.
>>>
>>> Then someone suggested a cracked intake- that fit the symptoms
>> perfectly.
>>> The issue would get worse as the engine warmed up but also, the severity
>>> would get worse over time. So it made perfect sense that a crack would
>>> open more as the engine wormed and get bigger over time.
>>>
>>> I scored a good intake and commenced to changing it. And when it was all
>>> back together there is NO CHANGEit still does not run right.
>>>
>>> So maybe the carb? The Revcon is sitting there, has not been run in
>> over a
>>> year. The original Toronado Carb has NEVER been rebuilt, but i swap it
>>> out and the Coach runs PERFECTLY!
>>>
>>> Ok, that was a long and winding road. Whatever is going on is happening
>> in
>>> the carb ONLY.
>>>
>>>
>>> Here's the symptoms- engine starts pretty easily, takes off smoothly and
>>> accelerates into second gear and then has no more power. If I give it
>> more
>>> gas is bogs down like it's gonna stall.
>>>
>>> This gets worse the longer i drive it (lately not more than a couple
>>> miles)
>>>
>>> This carb was freshly rebuilt for the Coop in 2013. it went 1000 miles
>> and
>>> did not move again so I'm not inclined to tear in all apart, it's not
>> like
>>> parts are worn or thousands of gallons of fuel have run through it.
>>>
>>> What Say the Brain Trust ?
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>> --
>>> Len and Pat Novak 1978 GMC Kingsley The Beast II with dash lights that
>>> work and labels you can see! Las Vegas, NV new email:
>> B52srule@gmail.com
>>> http://www.gmcmhphotos.com/photos/showgallery.php?cat=4375
>>> www.bdub.net/novak/
>>> _______________________________________________
>>> GMCnet mailing list
>>> Unsubscribe or Change List Options:
>>> _______________________________________________
>>> GMCnet mailing list
>>> Unsubscribe or Change List Options:
>>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>>
>
>
> --
> Jim Kanomata ASE
> Applied/GMC, Newark,CA
> jimk@appliedairfilters.com
> http://www.gmcrvparts.com
> 1-800-752-7502
>
--
Jim Kanomata ASE
Applied/GMC, Newark,CA
jimk@appliedairfilters.com
http://www.gmcrvparts.com
1-800-752-7502
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
|
|
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| Re: It was not a cracked intake- it was the carb. now what? [message #369251 is a reply to message #369243] |
Fri, 25 March 2022 08:04 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
|
Senior Member |
|
|
I'd do the quick cheap and dirty first - replace the filter in the carb inlet. Still have trouble, check the carb base for warping, if it's flat send it to a competent builder. Dick Patterson comes to mid. Or consider an upgrade to fuel injection.
--johnny
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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| Re: It was not a cracked intake- it was the carb. now what? [message #369252 is a reply to message #369243] |
Fri, 25 March 2022 08:31 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
|
Senior Member |
|
|
Guessing using data provided. Stuck power valve piston. Easy fix. Runs ok with choke on cold. As it warm up the rods are not moving up and down and as choke opens it goes flat as you open throttle.
20 mins to remove carb
20 mins to clean bench off
20 mins to open carb and remove and spray power valve and all passages
20 mins to reinstall carb.
(Generous time scales)
If carb was rebuilt as recently as you say, I bet the top gasket is still reusable. Spray straw all the emulsion tubes and passages w carb cleaner while apart. If you have not worked on Qjets feel free to ask any questions. Hidden screws etc.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: It was not a cracked intake- it was the carb. now what? [message #369253 is a reply to message #369252] |
Fri, 25 March 2022 08:51 |
hertfordnc
Messages: 1164
Registered: September 2009
Location: East NC
Karma: 0
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Senior Member |
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JohnL455 wrote on Fri, 25 March 2022 08:31Guessing using data provided. Stuck power valve piston. Easy fix. Runs ok with choke on cold. As it warm up the rods are not moving up and down and as choke opens it goes flat as you open throttle.
20 mins to remove carb
20 mins to clean bench off
20 mins to open carb and remove and spray power valve and all passages
20 mins to reinstall carb.
(Generous time scales)
If carb was rebuilt as recently as you say, I bet the top gasket is still reusable. Spray straw all the emulsion tubes and passages w carb cleaner while apart. If you have not worked on Qjets feel free to ask any questions. Hidden screws etc.
This is the answer i was hoping for.
I have very little carb experience but lots of experience opening up things i know nothing about.
I'll do some reasearch and get into itthis weekend- thanks
Dave & Ellen Silva
Hertford, NC
76 Birchaven, 1-ton and other stuff
Currently planning the Great american Road Trip Summer 2021
It's gonna take a lot of Adderall to get this thing right.
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| Re: It was not a cracked intake- it was the carb. now what? [message #369255 is a reply to message #369243] |
Fri, 25 March 2022 09:56 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Senior Member |
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There are 2 “hidden” screws in the primary throats. Don’t pry anything. If primary plunger is stuck down, spray in there as best you can. To remove it it needs to be free. You push down with finger and side step it it it pops the retainer out. To reinstall get rods in jets and depress with finger while reseating the plastic or phenolic retainer.
Remember only “2 fingers tight” mounting the carb to avoid warping.
John Lebetski
Woodstock, IL
77 Eleganza II
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| [GMCnet] Re: It was not a cracked intake- it was the carb. now what? [message #369256 is a reply to message #369244] |
Fri, 25 March 2022 10:15 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Senior Member |
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If your going to run a Toronado carb, your fuel consumption will be high
unless you replace the Power valve.
On Fri, Mar 25, 2022 at 8:04 AM James Hupy wrote:
> If you are separating the throttle body from the float bowl, there is also
> a screw in the near exact middle of the throttle body pointing upwards from
> the gasket surface between the throttle body and manifold. That screw is
> frequently loose and contributes to carb base warpage and fuel leaks. Don't
> ask me how I learned this one.
> Jim Hupy
> Salem, Oregon
>
> On Fri, Mar 25, 2022, 7:56 AM John R. Lebetski
> wrote:
>
>> There are 2 “hidden” screws in the primary throats. Don’t pry anything.
> If
>> primary plunger is stuck down, spray in there as best you can. To
>> remove it it needs to be free. You push down with finger and side step it
>> it it pops the retainer out. To reinstall get rods in jets and depress
> with
>> finger while reseating the plastic or phenolic retainer.
>> Remember only “2 fingers tight” mounting the carb to avoid warping.
>> --
>> John Lebetski
>> Woodstock, IL
>> 77 Eleganza II
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
--
Jim Kanomata ASE
Applied/GMC, Newark,CA
jimk@appliedairfilters.com
http://www.gmcrvparts.com
1-800-752-7502
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GMCnet mailing list
Unsubscribe or Change List Options:
Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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| Re: [GMCnet] Re: It was not a cracked intake- it was the carb. now what? [message #369260 is a reply to message #369256] |
Fri, 25 March 2022 12:18 |
hertfordnc
Messages: 1164
Registered: September 2009
Location: East NC
Karma: 0
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jimk wrote on Fri, 25 March 2022 10:15If your going to run a Toronado carb, your fuel consumption will be high
unless you replace the Power valve.
No, definitely not keeping the Toro carb. Just swapped it for trouble shooting- but damn it ran pretty good.
I finally got the coach going fast enough to be terrified by the sloppy steering. Dave Lenzi has shipped a used steering relay.
Dave & Ellen Silva
Hertford, NC
76 Birchaven, 1-ton and other stuff
Currently planning the Great american Road Trip Summer 2021
It's gonna take a lot of Adderall to get this thing right.
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| Re: It was not a cracked intake- it was the carb. now what? [message #369261 is a reply to message #369251] |
Fri, 25 March 2022 13:43 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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The lazy persons way to try before disassembling the carb. I got this from, Dick Paterson.
I had a GMC w/403 engine that sat for 19 years. I got it to start and barely run (very poorly).
I had disconnected the input hose to fuel pump and ran it on a temporary 5 gallon can of clean gasoline resting on the front bumper. With it running I switched the fuel input to straight carb cleaner and ran it at about 2000 rpm until the engine died. Then I let it soak for 24 hours.
The next day I reconnected the clean gas can to the fuel pump and cranked, and cranked, and cranked until some of the carb cleaner in the carb was replaced with fresh gas and the engine restarted. The engine now runs perfectly and I wish that my 455 in my own coach ran and started that well.
Try a 24 hour soaking with a carb full of pure carb cleaner before you tear into the carb.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: It was not a cracked intake- it was the carb. now what? [message #369265 is a reply to message #369243] |
Fri, 25 March 2022 20:18 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Senior Member |
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Smokey said 9 out of 10 carb problems are ignition.
Jim is correct about faulty mufflers.
And the power valve. BUT besides the power valve spring the GMC used, the GMC was the only Qjet made to use special triple tapered primary rods. This into from the Doug Roe Rochester carbs book.
John Lebetski
Woodstock, IL
77 Eleganza II
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