80 c30 went from no start to full throttle - The 1947 - Present Chevrolet & GMC Truck Message Board Network

jdf915 · 03-29-2015, 07:11 PM

Was needing to just move a trailer with my truck and spent 2 days on it and finally it starts and goes straight to full throttle and all the butterfly valves are nearly closed the only way to throttle it down is to use the choke. Need some help here guys cause I'm scratching my head here.

Liberty · 03-29-2015, 07:17 PM

Idle screws set wrong?

jdf915 · 03-29-2015, 07:26 PM

It ran previous to this encounter.

Liberty · 03-29-2015, 08:39 PM

What kind of carb you have on it?

Edit: wait just saw your signature that this truck is a diesel?

86c20 · 03-29-2015, 08:46 PM

if its diesel there are no butterflys there.

Liberty · 03-29-2015, 09:56 PM

Quote:

Originally Posted by 86c20

if its diesel there are no butterflys there.

Haha, thats why I asked! I know nothing of diesels!

I'd still lean on the fast idle being set high. Maybe even a stuck throttle.

jdf915 · 03-29-2015, 09:58 PM

Not a diesel yet. Carb is a quadrajet.

jdf915 · 03-29-2015, 10:02 PM

The only thing that I changed was get the rear two butterfly valves unstuck.

buddy_1 · 03-29-2015, 10:17 PM

Did you have the carb off ? Are the secondary butterflies catching on the base gasket ? Any vacuum hoses disconnected or split / cracked ?

jdf915 · 03-29-2015, 10:43 PM

No I don't have the carb off. No the valves are not catching. Almost new hoses.

cadillac_al · 03-30-2015, 06:45 AM

It still sounds like the secondaries are sticking open to me. I have had it happen to me several times when the carb has been sitting for a couple years.

jdf915 · 03-30-2015, 08:59 AM

What should I do to fix it.

geezer#99 · 03-30-2015, 10:10 AM

Quote:

Originally Posted by jdf915

What should I do to fix it.

Take a pic or two.
Both sides of the carb!

jdf915 · 03-30-2015, 11:50 AM

Here you go.

geezer#99 · 03-30-2015, 12:03 PM

A bit closer on both sides would help!

Liberty · 03-30-2015, 01:41 PM

That carb looks WORE OUT. I thought my old one was bad.
Probably would not hurt to rebuild this one.

motornut · 03-30-2015, 02:54 PM

can you see the butterflies after it starts?
any spring tension to hold the secondaries closed?

jdf915 · 03-30-2015, 05:16 PM

My dad says that we're going to rebuild it.

jdf915 · 03-30-2015, 05:36 PM

Where should I buy a rebuild kit.

jdf915 · 03-30-2015, 06:05 PM

Here's some better pics.

jdf915 · 03-30-2015, 06:09 PM

...

jdf915 · 03-30-2015, 06:13 PM

,,,

geezer#99 · 03-30-2015, 06:48 PM

Where's your secondary air valve dampner rod?

jdf915 · 03-30-2015, 07:42 PM

It's gone truck came that way.

geezer#99 · 03-30-2015, 07:51 PM

Does it still rev to the moon when you start it?
Have you turned down the high idle?

Here's a link on rebuilding your carb.
http://www.vetteprojects.com/kstyer/quadrajet.htm

03-29-2015, 07:11 PM	#1
jdf915 Registered User Join Date: Dec 2014 Location: Mt. Juliet Posts: 85	80 c30 went from no start to full throttle Was needing to just move a trailer with my truck and spent 2 days on it and finally it starts and goes straight to full throttle and all the butterfly valves are nearly closed the only way to throttle it down is to use the choke. Need some help here guys cause I'm scratching my head here. __________________ 1980 chevy c30 6.2L diesel swap here's the build thread http://67-72chevytrucks.com/vboard/s...=1#post7161431 1995 chevy c3500 6.5L diesel 1997 land rover disco I 6.2L diesel swap, MPG rumored at 26-28

03-29-2015, 07:17 PM	#2
Liberty Registered User Join Date: Feb 2015 Location: Bonham, Texas Posts: 241	Re: 80 c30 went from no start to full throttle Idle screws set wrong?

03-29-2015, 07:26 PM	#3
jdf915 Registered User Join Date: Dec 2014 Location: Mt. Juliet Posts: 85	Re: 80 c30 went from no start to full throttle It ran previous to this encounter. __________________ 1980 chevy c30 6.2L diesel swap here's the build thread http://67-72chevytrucks.com/vboard/s...=1#post7161431 1995 chevy c3500 6.5L diesel 1997 land rover disco I 6.2L diesel swap, MPG rumored at 26-28

03-29-2015, 08:39 PM	#4
Liberty Registered User Join Date: Feb 2015 Location: Bonham, Texas Posts: 241	Re: 80 c30 went from no start to full throttle What kind of carb you have on it? Edit: wait just saw your signature that this truck is a diesel?

03-29-2015, 08:46 PM	#5
86c20 Registered User Join Date: Mar 2012 Location: edgartown mass Posts: 852	Re: 80 c30 went from no start to full throttle if its diesel there are no butterflys there. __________________ 1986 c20 "the hillbilly" 350 sm465 3.42gears 21mpg at 70mph 1985 k30 "the ice cream truck from hell" no rust az truck 197-8??? c30 "ramp truck" 454 1978 monte carlo 350 350th with 2.73 gears. no rust. sc car

03-29-2015, 09:58 PM	#7
jdf915 Registered User Join Date: Dec 2014 Location: Mt. Juliet Posts: 85	Re: 80 c30 went from no start to full throttle Not a diesel yet. Carb is a quadrajet. __________________ 1980 chevy c30 6.2L diesel swap here's the build thread http://67-72chevytrucks.com/vboard/s...=1#post7161431 1995 chevy c3500 6.5L diesel 1997 land rover disco I 6.2L diesel swap, MPG rumored at 26-28

03-29-2015, 10:02 PM	#8
jdf915 Registered User Join Date: Dec 2014 Location: Mt. Juliet Posts: 85	Re: 80 c30 went from no start to full throttle The only thing that I changed was get the rear two butterfly valves unstuck. __________________ 1980 chevy c30 6.2L diesel swap here's the build thread http://67-72chevytrucks.com/vboard/s...=1#post7161431 1995 chevy c3500 6.5L diesel 1997 land rover disco I 6.2L diesel swap, MPG rumored at 26-28

03-29-2015, 10:17 PM	#9
buddy_1 Registered User Join Date: Dec 2013 Location: Humble, Texas Posts: 185	Re: 80 c30 went from no start to full throttle Did you have the carb off ? Are the secondary butterflies catching on the base gasket ? Any vacuum hoses disconnected or split / cracked ? __________________ I know the "VOICES" aren't real but they have some great ideas. 1978 GMC Sierra Classic C25 1983 Datsun 280ZX Turbo 1997 Chevy Cheyenne K2500 1999 Polaris Sport 400

03-29-2015, 10:43 PM	#10
jdf915 Registered User Join Date: Dec 2014 Location: Mt. Juliet Posts: 85	Re: 80 c30 went from no start to full throttle No I don't have the carb off. No the valves are not catching. Almost new hoses. __________________ 1980 chevy c30 6.2L diesel swap here's the build thread http://67-72chevytrucks.com/vboard/s...=1#post7161431 1995 chevy c3500 6.5L diesel 1997 land rover disco I 6.2L diesel swap, MPG rumored at 26-28

03-30-2015, 06:45 AM	#11
cadillac_al Registered User Join Date: Oct 2013 Location: Maine Posts: 2,375	Re: 80 c30 went from no start to full throttle It still sounds like the secondaries are sticking open to me. I have had it happen to me several times when the carb has been sitting for a couple years. __________________ 76 Chevy K20 76 GMC K15 77 Chevy C10 77 Chevy K10

03-30-2015, 08:59 AM	#12
jdf915 Registered User Join Date: Dec 2014 Location: Mt. Juliet Posts: 85	Re: 80 c30 went from no start to full throttle What should I do to fix it. __________________ 1980 chevy c30 6.2L diesel swap here's the build thread http://67-72chevytrucks.com/vboard/s...=1#post7161431 1995 chevy c3500 6.5L diesel 1997 land rover disco I 6.2L diesel swap, MPG rumored at 26-28

03-30-2015, 11:50 AM	#14
jdf915 Registered User Join Date: Dec 2014 Location: Mt. Juliet Posts: 85	Re: 80 c30 went from no start to full throttle Here you go. Attached Images __________________ 1980 chevy c30 6.2L diesel swap here's the build thread http://67-72chevytrucks.com/vboard/s...=1#post7161431 1995 chevy c3500 6.5L diesel 1997 land rover disco I 6.2L diesel swap, MPG rumored at 26-28

03-30-2015, 12:03 PM	#15
geezer#99 Registered User Join Date: Aug 2009 Location: Bowser Posts: 13,731	Re: 80 c30 went from no start to full throttle A bit closer on both sides would help!

03-30-2015, 01:41 PM	#16
Liberty Registered User Join Date: Feb 2015 Location: Bonham, Texas Posts: 241	Re: 80 c30 went from no start to full throttle That carb looks WORE OUT. I thought my old one was bad. Probably would not hurt to rebuild this one.

03-30-2015, 02:54 PM	#17
motornut 78K & 79C Jimmys Join Date: Nov 2009 Location: Ottawa Ont CANADA Posts: 7,901	Re: 80 c30 went from no start to full throttle can you see the butterflies after it starts? any spring tension to hold the secondaries closed? Attached Images __________________ John 1978 GMCJimmy4X4-350/203 1979 GMCJimmy4X2-305/350



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03-30-2015, 05:16 PM	#18
jdf915 Registered User Join Date: Dec 2014 Location: Mt. Juliet Posts: 85	Re: 80 c30 went from no start to full throttle My dad says that we're going to rebuild it. __________________ 1980 chevy c30 6.2L diesel swap here's the build thread http://67-72chevytrucks.com/vboard/s...=1#post7161431 1995 chevy c3500 6.5L diesel 1997 land rover disco I 6.2L diesel swap, MPG rumored at 26-28

03-30-2015, 05:36 PM	#19
jdf915 Registered User Join Date: Dec 2014 Location: Mt. Juliet Posts: 85	Re: 80 c30 went from no start to full throttle Where should I buy a rebuild kit. __________________ 1980 chevy c30 6.2L diesel swap here's the build thread http://67-72chevytrucks.com/vboard/s...=1#post7161431 1995 chevy c3500 6.5L diesel 1997 land rover disco I 6.2L diesel swap, MPG rumored at 26-28

03-30-2015, 06:05 PM	#20
jdf915 Registered User Join Date: Dec 2014 Location: Mt. Juliet Posts: 85	Re: 80 c30 went from no start to full throttle Here's some better pics. Attached Images __________________ 1980 chevy c30 6.2L diesel swap here's the build thread http://67-72chevytrucks.com/vboard/s...=1#post7161431 1995 chevy c3500 6.5L diesel 1997 land rover disco I 6.2L diesel swap, MPG rumored at 26-28

03-30-2015, 06:09 PM	#21
jdf915 Registered User Join Date: Dec 2014 Location: Mt. Juliet Posts: 85	Re: 80 c30 went from no start to full throttle ... Attached Images __________________ 1980 chevy c30 6.2L diesel swap here's the build thread http://67-72chevytrucks.com/vboard/s...=1#post7161431 1995 chevy c3500 6.5L diesel 1997 land rover disco I 6.2L diesel swap, MPG rumored at 26-28

03-30-2015, 06:13 PM	#22
jdf915 Registered User Join Date: Dec 2014 Location: Mt. Juliet Posts: 85	Re: 80 c30 went from no start to full throttle ,,, Attached Images __________________ 1980 chevy c30 6.2L diesel swap here's the build thread http://67-72chevytrucks.com/vboard/s...=1#post7161431 1995 chevy c3500 6.5L diesel 1997 land rover disco I 6.2L diesel swap, MPG rumored at 26-28

03-30-2015, 06:48 PM	#23
geezer#99 Registered User Join Date: Aug 2009 Location: Bowser Posts: 13,731	Re: 80 c30 went from no start to full throttle Where's your secondary air valve dampner rod?

03-30-2015, 07:42 PM	#24
jdf915 Registered User Join Date: Dec 2014 Location: Mt. Juliet Posts: 85	Re: 80 c30 went from no start to full throttle It's gone truck came that way. __________________ 1980 chevy c30 6.2L diesel swap here's the build thread http://67-72chevytrucks.com/vboard/s...=1#post7161431 1995 chevy c3500 6.5L diesel 1997 land rover disco I 6.2L diesel swap, MPG rumored at 26-28

03-30-2015, 07:51 PM	#25
geezer#99 Registered User Join Date: Aug 2009 Location: Bowser Posts: 13,731	Re: 80 c30 went from no start to full throttle Does it still rev to the moon when you start it? Have you turned down the high idle? Here's a link on rebuilding your carb. http://www.vetteprojects.com/kstyer/quadrajet.htm

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