Help!!
Thread Starter
Cruising
Joined: Jun 2010
Posts: 12
Likes: 0
Help!!
have recently developed a problem which has myself and local experts a little perplexed
after giving the car 75' a little burst from cold it has developed a serious hesitation especialy on cross over from idle to pump jets.
Had timing checked, pump adjustments checked ,new distrubutor cap ,leads.plugs,coil, and everything seems okay
Am now considering a new distrubutor but am told the electric ignition either works or doesnt so this should not be the problem? is this so ??
I am, and have been running for the past three years, holly 650 double pumper and open manifold but nothing changed there and as this fault started instantly cant see this being a problem !
would suggest it is the original distrubutor or a like for like replacement
any ideas or suggestions would be appreciated
after giving the car 75' a little burst from cold it has developed a serious hesitation especialy on cross over from idle to pump jets.
Had timing checked, pump adjustments checked ,new distrubutor cap ,leads.plugs,coil, and everything seems okay
Am now considering a new distrubutor but am told the electric ignition either works or doesnt so this should not be the problem? is this so ??
I am, and have been running for the past three years, holly 650 double pumper and open manifold but nothing changed there and as this fault started instantly cant see this being a problem !
would suggest it is the original distrubutor or a like for like replacement
any ideas or suggestions would be appreciated
Safety Car
Joined: Sep 2007
Posts: 4,443
Likes: 326
From: Indy Indiana
maybe I am old or something but I am confused by some of the terms here.
what does a little burst from cold mean?
what does cross over from idle to pump jets mean?
how are pump adjustments checked?
what is an open manifold?
what does a little burst from cold mean?
what does cross over from idle to pump jets mean?
how are pump adjustments checked?
what is an open manifold?
Thread Starter
Cruising
Joined: Jun 2010
Posts: 12
Likes: 0
help
start up cold engine and give reasonable throttle through gears ( being Manual) sorry stick shift
secondly attempt to describe the throttle opening from idle to main jet
thirdly, feeler gauge tolerance under pump adjustment lever at stationary but with throttle at fully open
lastly, my best desciption of a slightly raised alluminium manifold which basicaly has just a square opening without internal chambering ( I think!)
Thread Starter
Cruising
Joined: Jun 2010
Posts: 12
Likes: 0
help
Instructor
Joined: May 2010
Posts: 172
Likes: 3
From: Hesperia California
hesitation
Are you saying that when your car is cold and choke is on,you are driving and when you touch the gas it hesitates/stumbles ?. If so 7T1vette has answered your question, and or maybe your accelerator pump is bad, If I am understanding you correctly, just thoughts, good luck.
Race Director
Joined: Dec 1999
Posts: 11,091
Likes: 990
From: Sierra Foothills CA
I wouldn't touch the ignition until I know the carb is working properly. As stated by others, make sure the choke is OK and then check/replace the accelerator pumps (both primary and secondary). They should start squirting gas as soon as you see the cams for the pumps come into play. If you're not sure how to do that an alternative is to borrow a working carb and see if that eliminates the problem. Good luck. 
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Thread Starter
Cruising
Joined: Jun 2010
Posts: 12
Likes: 0
help
Thanks for the response and advise
currently running without a choke either manual or electric and chock butterfly fixed in open position
on activating primary pump plenty of fuel seems to be present but not tried secondary as I feel the fault is evident too early for the secondary pump to be an issue?
am ignorant as to the workings of the carb internals and wonder could there be a blockage or something seerate from the pump jets?
currently have booked the car in to a local specialist and know he is not in favour of the large carb currently installed but hoped to find a solution rather than be forced into fitting another carb and even another manifold as being suggested at this time
is there a maintenance or breakdown information on areas that I could carry out myself
currently running without a choke either manual or electric and chock butterfly fixed in open position
on activating primary pump plenty of fuel seems to be present but not tried secondary as I feel the fault is evident too early for the secondary pump to be an issue?
am ignorant as to the workings of the carb internals and wonder could there be a blockage or something seerate from the pump jets?
currently have booked the car in to a local specialist and know he is not in favour of the large carb currently installed but hoped to find a solution rather than be forced into fitting another carb and even another manifold as being suggested at this time
is there a maintenance or breakdown information on areas that I could carry out myself
Race Director
Joined: Dec 1999
Posts: 11,091
Likes: 990
From: Sierra Foothills CA
A Google search for Holley carbs will get you a lot of useful info along with some exploded diagrams. If you've been running w/o a choke all along that really shouldn't be your problem.
The link below shows photos at the bottom of the page of what the 650 looks like when off the car and inverted. You can see that the accel. pump diaphragms are located under the end sections of the carb and are inside a cover that's secured by 4 phillips head screws. If you decide to tackle replacing the diaphragms but have never done it before just look carefully as you pull the cover off because there's a spring in there that needs to go back where it came from. The arm that is attached to the cover also needs to go as pictured. The assembly that it contacts needs to be positioned as it's shown in the picture. It rotates during disassembly and you'll need to have it in proper position before tightening the cover back into place. This should all make sense if you disassemble it but if you want to be safe get a buddy with experience to help. It's not really that complicated- probably harder to describe than to do! Here you go-
http://forums.corral.net/forums/5-0-...out-vents.html
The link below shows photos at the bottom of the page of what the 650 looks like when off the car and inverted. You can see that the accel. pump diaphragms are located under the end sections of the carb and are inside a cover that's secured by 4 phillips head screws. If you decide to tackle replacing the diaphragms but have never done it before just look carefully as you pull the cover off because there's a spring in there that needs to go back where it came from. The arm that is attached to the cover also needs to go as pictured. The assembly that it contacts needs to be positioned as it's shown in the picture. It rotates during disassembly and you'll need to have it in proper position before tightening the cover back into place. This should all make sense if you disassemble it but if you want to be safe get a buddy with experience to help. It's not really that complicated- probably harder to describe than to do! Here you go-
http://forums.corral.net/forums/5-0-...out-vents.html
Thread Starter
Cruising
Joined: Jun 2010
Posts: 12
Likes: 0
A Google search for Holley carbs will get you a lot of useful info along with some exploded diagrams. If you've been running w/o a choke all along that really shouldn't be your problem.
The link below shows photos at the bottom of the page of what the 650 looks like when off the car and inverted. You can see that the accel. pump diaphragms are located under the end sections of the carb and are inside a cover that's secured by 4 phillips head screws. If you decide to tackle replacing the diaphragms but have never done it before just look carefully as you pull the cover off because there's a spring in there that needs to go back where it came from. The arm that is attached to the cover also needs to go as pictured. The assembly that it contacts needs to be positioned as it's shown in the picture. It rotates during disassembly and you'll need to have it in proper position before tightening the cover back into place. This should all make sense if you disassemble it but if you want to be safe get a buddy with experience to help. It's not really that complicated- probably harder to describe than to do! Here you go-
http://forums.corral.net/forums/5-0-...out-vents.html
The link below shows photos at the bottom of the page of what the 650 looks like when off the car and inverted. You can see that the accel. pump diaphragms are located under the end sections of the carb and are inside a cover that's secured by 4 phillips head screws. If you decide to tackle replacing the diaphragms but have never done it before just look carefully as you pull the cover off because there's a spring in there that needs to go back where it came from. The arm that is attached to the cover also needs to go as pictured. The assembly that it contacts needs to be positioned as it's shown in the picture. It rotates during disassembly and you'll need to have it in proper position before tightening the cover back into place. This should all make sense if you disassemble it but if you want to be safe get a buddy with experience to help. It's not really that complicated- probably harder to describe than to do! Here you go-
http://forums.corral.net/forums/5-0-...out-vents.html
will take a look at site as suggested thanks guys
Thread Starter
Cruising
Joined: Jun 2010
Posts: 12
Likes: 0
Thread Starter
Cruising
Joined: Jun 2010
Posts: 12
Likes: 0
Hi all
Have taken the easy option as local deales had a new 600cfm Holley which when fitted cured the problem
will have to look deeper into my old one to see what was wrong but can now do it at leisure with the car on the road
thanks for your posts
Have taken the easy option as local deales had a new 600cfm Holley which when fitted cured the problem
will have to look deeper into my old one to see what was wrong but can now do it at leisure with the car on the road
thanks for your posts