| How loud should my carburetor be ?? [message #210474] |
Sun, 09 June 2013 15:08  |
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SteveW
Messages: 538
Registered: June 2005
Location: Southern California - Ora...
Karma: 1
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Greetings all - and THANKS in advance for any ideas or suggestions.
I've got a problem with no power at low RPMs. The coach really has a hard time getting rolling. Bogs down quite a bit.
Suspecting a carb problem, I took off the air cleaner and drove around the block (engine cover off) to observe things. At idle, everything sounds fine. With a bit of throttle - it sounds like the hose off an air compressor. Really load air hissing noise. Really loud.
There are no really obvious vacuum leaks or disconnects.
And I'm not sure that the "power valve" or "power piston" on the carb is working. I push on it with a straw and there's no movement.
Any ideas ??
I haven't checked vacuum controlled advance or retard yet... it feels like a fuel delivery problem.
Steve W
Southern California
1973 23'
Steve W
1973 : 23'
Southern California
[Updated on: Sun, 09 June 2013 15:34] Report message to a moderator |
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| Re: How loud should my carburetor be ?? [message #210480 is a reply to message #210474] |
Sun, 09 June 2013 16:23  |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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| SteveW wrote on Sun, 09 June 2013 16:08 |
Greetings all - and THANKS in advance for any ideas or suggestions.
I've got a problem with no power at low RPMs. The coach really has a hard time getting rolling. Bogs down quite a bit.
Suspecting a carb problem, I took off the air cleaner and drove around the block (engine cover off) to observe things. At idle, everything sounds fine. With a bit of throttle - it sounds like the hose off an air compressor. Really load air hissing noise. Really loud.
There are no really obvious vacuum leaks or disconnects.
And I'm not sure that the "power valve" or "power piston" on the carb is working. I push on it with a straw and there's no movement.
Any ideas ??
I haven't checked vacuum controlled advance or retard yet... it feels like a fuel delivery problem.
Steve W
Southern California
1973 23'
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Steve,
We I get my foot in mine, it is LOUD. My cpoach can be pretty quick off the line even if I don't open the secondaries (aka flush it).
In as much as I don't have that problem at all, I'm guessing something is amiss with your carburetor.
If you push where the power valve is supposed to be and it doesn't move. then there surely is.
There is a link to a Quadrajet manual.
http://oldcarmanualproject.com/manuals/Carbs/Rochester/QJet/index.htm
There are many people here that know more about the RQJ than I do, and you can probably use the manual to get smart enough to get a good start on asking the right questions.
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] How loud should my carburetor [message #210481 is a reply to message #210474] |
Sun, 09 June 2013 16:23 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Try advancing the dist timing.
On Sun, Jun 9, 2013 at 1:08 PM, Steve Weinstock <steve.weinstock@cox.net>wrote:
>
>
> Greetings all - and THANKS in advance for any ideas or suggestions.
>
> I've got a problem with no power at low RPMs. The coach really has a hard
> time getting rolling. Bogs down quite a bit.
>
> Suspecting a carb problem, I took off the air cleaner and drove around the
> block (engine cover off) to observe things. At idle, everything sounds
> fine. With a bit of throttle - it sounds like the hose off an air
> compressor. Really load air hissing noise. Really loud.
>
> There are no really obvious vacuum leaks or disconnects.
>
> And I'm not sure that the "power valve" or "power piston" on the carb is
> working. I push on it with a straw and there's no movement.
>
> Any ideas ??
>
> I haven't checked vacuum controlled advance or retard yet... it feels like
> a fuel delivery problem.
>
> Steve W
> Southern California
> 1973 23'
>
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
--
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
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| Re: How loud should my carburetor be ?? [message #210482 is a reply to message #210474] |
Sun, 09 June 2013 16:25 |
tphipps
Messages: 3005
Registered: August 2004
Location: Spanish Fort, AL
Karma: 9
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A uncovered, no air cleaner carb will be loud. quick math will tell you how much air is moving into the engine. Lots of it aiming for the carb.
Choke stuck open on a cold engine will bog down like crazy.
Plugged fuel filter?
Lots of little things to drive you nuts.
Tom, MS II
2012 Phoenix Cruiser model 2552
KA4CSG
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| Re: How loud should my carburetor be ?? [message #210487 is a reply to message #210474] |
Sun, 09 June 2013 16:36 |
armandminnie
Messages: 864
Registered: May 2009
Location: Marana, AZ
Karma: 2
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| SteveW wrote on Sun, 09 June 2013 13:08 |
And I'm not sure that the "power valve" or "power piston" on the carb is working. I push on it with a straw and there's no movement.
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Steve, last summer I had a similar problem and it turned out to be some dirt in the carb. I had to take the top (the "air horn") off and clean the passages with some carb cleaner. The process is documented in the maintenance manual. Regarding the "power piston" movement - the reason they say to use a straw is because the implement has to be round in order to get close enough to the side of the tube on the front side to contact the almost-impossible-to-get-to top of the piston. You really have to shine a light down in there and look to see what you are trying to push on.
Armand Minnie
Marana, AZ
'76 Eleganza II TZE166V103202
visit my gmc blog
click here to visit gmcws.org
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| Re: How loud should my carburetor be ?? [message #210511 is a reply to message #210474] |
Sun, 09 June 2013 18:58 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Straw test is engine off. Otherwise it's sucked down and you can't push it down. I don't like Qjet work on vehicle. Easy to drop a throat screw or clip down primaries. Light throttle to move the coach would keep the powervalve in lean mode (down) so doubt that is it. Other answer is deafening high frequency on primaries and added roar on secondaries with cleaner off and no hatch.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: [GMCnet] How loud should my carburetor [message #210517 is a reply to message #210481] |
Sun, 09 June 2013 20:01 |
powerjon
Messages: 2446
Registered: January 2004
Karma: 5
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Jim is right, if you're timing is retarded it won't with a darn and have no power.
JR Wright
On Jun 9, 2013, at 5:23 PM, Jim Kanomata <jimkanomata@gmail.com> wrote:
> Try advancing the dist timing.
>
> On Sun, Jun 9, 2013 at 1:08 PM, Steve Weinstock <steve.weinstock@cox.net>wrote:
>
>>
>>
>> Greetings all - and THANKS in advance for any ideas or suggestions.
>>
>> I've got a problem with no power at low RPMs. The coach really has a hard
>> time getting rolling. Bogs down quite a bit.
>>
>> Suspecting a carb problem, I took off the air cleaner and drove around the
>> block (engine cover off) to observe things. At idle, everything sounds
>> fine. With a bit of throttle - it sounds like the hose off an air
>> compressor. Really load air hissing noise. Really loud.
>>
>> There are no really obvious vacuum leaks or disconnects.
>>
>> And I'm not sure that the "power valve" or "power piston" on the carb is
>> working. I push on it with a straw and there's no movement.
>>
>> Any ideas ??
>>
>> I haven't checked vacuum controlled advance or retard yet... it feels like
>> a fuel delivery problem.
>>
>> Steve W
>> Southern California
>> 1973 23'
>>
>>
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>>
>
>
>
> --
> Jim Kanomata
> Applied/GMC, Fremont,CA
> jimk@appliedairfilters.com
> http://www.appliedgmc.com
> 1-800-752-7502
> _______________________________________________
> 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
J.R. Wright
GMC GreatLaker
GMC Eastern States
GMCMI
78 30' Buskirk Stretch
75 Avion Under Reconstruction
Michigan
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| Re: How loud should my carburetor be ?? [message #210531 is a reply to message #210474] |
Sun, 09 June 2013 21:47 |
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SteveW
Messages: 538
Registered: June 2005
Location: Southern California - Ora...
Karma: 1
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Senior Member |
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THANK YOU Matt, Jim, Tom, Armand, John, and JR !!!
I ran out of time and energy today...
The coach is back at the storage yard and I plan to mess with it during the week - next weekend for sure.
Before my posting, I sprayed some carb cleaner into it. Might have helped a little bit - certainly didn't make it worse.
Advancing the timing is my next action. But - the problem is somewhat new... Could my timing have moved on its own ??
Worst case - the Pacific Cruisers are having a small rally next weekend... No doubt we can sort it out there.
Steve W
Steve W
1973 : 23'
Southern California
[Updated on: Sun, 09 June 2013 22:19] Report message to a moderator |
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| Re: How loud should my carburetor be ?? [message #210537 is a reply to message #210474] |
Sun, 09 June 2013 22:48 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Why would the timing be in need of being initial advance increased? Magical change in storage? Wrong to mess with that if it was ok last drive. What would retard it is worn timing set, stuck mechanical advance, stuck/ leaking vac advance, bad vac line or line off. You can check above with timing light rather than guessing and ruining engine. Visual inspection is key here inside and outside the distributor. A broken rotor ( contact swung back) should be looked for along with binding (dry grease).
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: How loud should my carburetor be ?? [message #210566 is a reply to message #210474] |
Mon, 10 June 2013 09:31 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Senior Member |
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The exposed weights and pins and pivots can be lubricated, but if it is dry where the plate moves on the shaft it is best disassembled according to Dick P at his presentation. I would use something like a Mobil 1 red grease but only a film so thin you don't see it so it won't be slung. To properly grease the plate pivot you have to remove dist (retime) and knock out roll pin on gear. You have to get washers back the right way as well as clocking everthing correctly. Olds rotate opposite of most so washers are placed differently. If plate were binding on mine I'd try a drop of oil from a precision spout oiler first. JWID. You may want to send the dist to Dick over the winter for a redo. We first have to determine if this is an ignition or carb problem.
John Lebetski
Woodstock, IL
77 Eleganza II
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