Car dies when I turn...
Thread Starter
Melting Slicks
Joined: Jan 2003
Posts: 2,713
Likes: 31
From: Shreveport LA
LA Events Coordinator
Car dies when I turn...
1975 convertible with automatic transmission and Holley 650 4-barrel.... Happens everytime... cold, hot...turning hard (coming up to a corner quickly) or turning regularly...it doesn't matter. I checked the bowls float levels...right below the sight line...fuel trickles out when I shake the car. Checked the air/fuel mixture with vacuum gauge....vacuum maxed out at 15 inches. The car starts with no problems and runs smooth... the auto choke works. And when I "goose it" while it's parked...no problems....she responds like normal...immediate and smooth. BUT when I drive it and WOT, she hesitates...spits and sputter a little.
Cleaned the carb with Gumout spray...inside & outside while the engine was running (per the instructions on the can) Took her out and the same thing....
Thinking of converting to a TBI system..but man, the COST!!!
HELP!!!.
Cleaned the carb with Gumout spray...inside & outside while the engine was running (per the instructions on the can) Took her out and the same thing....
Thinking of converting to a TBI system..but man, the COST!!!
HELP!!!.
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,810
From: Cool Northern Michigan
Nothing wrong with a Holley 650 (bias). Lets blame the Ethanol, its more fun.
Your spraying of carb cleaner is a wonderful thing to do a couples times a year. Unfortunately, it does nothing to the jets which I suspect one of them is plugged with varnish. That would also explain the WOT hesitation. Only one jet is functional. That would also explain good idle and revving characteristics. Also explains the stalling when turning.
So, with that in mind, its time to remove the fuel bowls and soak the metering blocks in a bucket of carb cleaner (Amazon). Remove the Power Valve to avoid any chemical damage.
While you are in there, take note of the floats. Do they seem saturated and are likely sinking? After a good cleaning, install new "blue" fuel bowl & metering block gaskets. Use nothing but genuine Holley parts and you should be good to go.
Your spraying of carb cleaner is a wonderful thing to do a couples times a year. Unfortunately, it does nothing to the jets which I suspect one of them is plugged with varnish. That would also explain the WOT hesitation. Only one jet is functional. That would also explain good idle and revving characteristics. Also explains the stalling when turning.
So, with that in mind, its time to remove the fuel bowls and soak the metering blocks in a bucket of carb cleaner (Amazon). Remove the Power Valve to avoid any chemical damage.
While you are in there, take note of the floats. Do they seem saturated and are likely sinking? After a good cleaning, install new "blue" fuel bowl & metering block gaskets. Use nothing but genuine Holley parts and you should be good to go.
Last edited by HeadsU.P.; Apr 22, 2019 at 04:48 PM.
Race Director
Joined: May 2006
Posts: 18,737
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when you adjusted the mixture screws and were turning them clockwise, did you reach a point with both screws that the idle started to drop?
Do you have a smooth idle with the engine in drive?
did you pull the spark plugs to check their condition?
Do you have a smooth idle with the engine in drive?
did you pull the spark plugs to check their condition?
Is my vette stock?? HAHA
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From: Im not allowed to tell you
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Do you happen to have a fuel pressure gauge in line with your fuel supply line. I was gettting some irregular performance and I noticed my car was sometimes sputtering out of the blue. I didnt adjust of change anything, it just started happening. I had a pressure gauge after my regulator and thoguht it was the regulator. I added a second pressure gauge just after the pump as another tool to solve the problem. It did.
My fuel pump failed internally. The pin that the arm pivoted on pulled out of the casting. It still worked but i was barley getting 3 psi. So it would run but when I got on it, it would drain the bowls faster than they could keep up. It could be a similar problem for you . If rebuilding the carb doesnt do it, check your pressure. It may not explain the dieing in the turns but you never know
My fuel pump failed internally. The pin that the arm pivoted on pulled out of the casting. It still worked but i was barley getting 3 psi. So it would run but when I got on it, it would drain the bowls faster than they could keep up. It could be a similar problem for you . If rebuilding the carb doesnt do it, check your pressure. It may not explain the dieing in the turns but you never know
Thread Starter
Melting Slicks
Joined: Jan 2003
Posts: 2,713
Likes: 31
From: Shreveport LA
LA Events Coordinator
Thread Starter
Melting Slicks
Joined: Jan 2003
Posts: 2,713
Likes: 31
From: Shreveport LA
LA Events Coordinator
Do you happen to have a fuel pressure gauge in line with your fuel supply line. I was gettting some irregular performance and I noticed my car was sometimes sputtering out of the blue. I didnt adjust of change anything, it just started happening. I had a pressure gauge after my regulator and thoguht it was the regulator. I added a second pressure gauge just after the pump as another tool to solve the problem. It did.
My fuel pump failed internally. The pin that the arm pivoted on pulled out of the casting. It still worked but i was barley getting 3 psi. So it would run but when I got on it, it would drain the bowls faster than they could keep up. It could be a similar problem for you . If rebuilding the carb doesnt do it, check your pressure. It may not explain the dieing in the turns but you never know
My fuel pump failed internally. The pin that the arm pivoted on pulled out of the casting. It still worked but i was barley getting 3 psi. So it would run but when I got on it, it would drain the bowls faster than they could keep up. It could be a similar problem for you . If rebuilding the carb doesnt do it, check your pressure. It may not explain the dieing in the turns but you never know
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Thread Starter
Melting Slicks
Joined: Jan 2003
Posts: 2,713
Likes: 31
From: Shreveport LA
LA Events Coordinator
Do you happen to have a fuel pressure gauge in line with your fuel supply line. I was gettting some irregular performance and I noticed my car was sometimes sputtering out of the blue. I didnt adjust of change anything, it just started happening. I had a pressure gauge after my regulator and thoguht it was the regulator. I added a second pressure gauge just after the pump as another tool to solve the problem. It did.
My fuel pump failed internally. The pin that the arm pivoted on pulled out of the casting. It still worked but i was barley getting 3 psi. So it would run but when I got on it, it would drain the bowls faster than they could keep up. It could be a similar problem for you . If rebuilding the carb doesnt do it, check your pressure. It may not explain the dieing in the turns but you never know
My fuel pump failed internally. The pin that the arm pivoted on pulled out of the casting. It still worked but i was barley getting 3 psi. So it would run but when I got on it, it would drain the bowls faster than they could keep up. It could be a similar problem for you . If rebuilding the carb doesnt do it, check your pressure. It may not explain the dieing in the turns but you never know
Thread Starter
Melting Slicks
Joined: Jan 2003
Posts: 2,713
Likes: 31
From: Shreveport LA
LA Events Coordinator
Nothing wrong with a Holley 650 (bias). Lets blame the Ethanol, its more fun.
Your spraying of carb cleaner is a wonderful thing to do a couples times a year. Unfortunately, it does nothing to the jets which I suspect one of them is plugged with varnish. That would also explain the WOT hesitation. Only one jet is functional. That would also explain good idle and revving characteristics. Also explains the stalling when turning.
So, with that in mind, its time to remove the fuel bowls and soak the metering blocks in a bucket of carb cleaner (Amazon). Remove the Power Valve to avoid any chemical damage.
While you are in there, take note of the floats. Do they seem saturated and are likely sinking? After a good cleaning, install new "blue" fuel bowl & metering block gaskets. Use nothing but genuine Holley parts and you should be good to go.
Your spraying of carb cleaner is a wonderful thing to do a couples times a year. Unfortunately, it does nothing to the jets which I suspect one of them is plugged with varnish. That would also explain the WOT hesitation. Only one jet is functional. That would also explain good idle and revving characteristics. Also explains the stalling when turning.
So, with that in mind, its time to remove the fuel bowls and soak the metering blocks in a bucket of carb cleaner (Amazon). Remove the Power Valve to avoid any chemical damage.
While you are in there, take note of the floats. Do they seem saturated and are likely sinking? After a good cleaning, install new "blue" fuel bowl & metering block gaskets. Use nothing but genuine Holley parts and you should be good to go.
Last edited by vetteguy75; Apr 23, 2019 at 09:57 PM.
Melting Slicks
Joined: Jul 2006
Posts: 2,291
Likes: 493
From: Salmon Arm, BC
When was the last time the carb was rebuilt? If it sat for any period of time it's likely that some varnish or crap has come loose and blocked some internal passages.
They are very easy to rebuild, and I'm sure you'll find a great vid on youtube to guide you through it if you haven't done it before.
They are very easy to rebuild, and I'm sure you'll find a great vid on youtube to guide you through it if you haven't done it before.
Thread Starter
Melting Slicks
Joined: Jan 2003
Posts: 2,713
Likes: 31
From: Shreveport LA
LA Events Coordinator
When was the last time the carb was rebuilt? If it sat for any period of time it's likely that some varnish or crap has come loose and blocked some internal passages.
They are very easy to rebuild, and I'm sure you'll find a great vid on youtube to guide you through it if you haven't done it before.
They are very easy to rebuild, and I'm sure you'll find a great vid on youtube to guide you through it if you haven't done it before.
Is my vette stock?? HAHA
Joined: Oct 2015
Posts: 20,216
Likes: 9,354
From: Im not allowed to tell you
2020 C3 of the Year Finalist - Modified
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
Maybe you have water in your tank and its been getting sucked up into your system. I wouldnt think varnish would form from one month of sitting. when you drain your carb, can you catch it all in a glass jar?
When was the last time the fuel filter was replaced?
When was the last time the fuel filter was replaced?
Race Director
Joined: May 2006
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Jets
Thanks for your input. Lars (of the Corvette Forum...Carb Guru) rebuilt it about 7-8 years ago and it has been running perfectly since the first day I installed it back. It has been sitting for about a month (really bad weather) and I just now started driving her again. I am going to remove the fuel bowls and metering block, remove the power valve and soak it in some carb cleaner. Also going to clean out the jets...put new gaskets, reassemble and see what happens. Question...if I decide NOT to remove the metering block, can I just clean the jets with Summit Racing Carb jet brushes and some Gunk spray carb cleaner?
Team Owner
Joined: Oct 2004
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From: altered state
St. Jude Donor '05
Wonder if your floats are too low, and some passage is getting uncovered when you turn hard?
Try raising them up some see what happens, if it runs good the rest of the time I dont see the need to take it apart.
Try raising them up some see what happens, if it runs good the rest of the time I dont see the need to take it apart.
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,810
From: Cool Northern Michigan
Just remove the bowls, clean. Remove the metering blocks and clean. Its easy on a Holley. Take note how the accelerator pump arm goes back together. Clean those jets. Do one set at a time so you don't mix them up. Primary will be different size than secondary.
Also take note how the new gasket should go on the part exactly like the old gasket. If you flip them 180* passages will be blocked off.
Use new blue Holley gaskets. Both the bowl and metering block gaskets are sold in pairs. Check out Summit for those.
Last edited by HeadsU.P.; Apr 24, 2019 at 08:48 PM.
Thread Starter
Melting Slicks
Joined: Jan 2003
Posts: 2,713
Likes: 31
From: Shreveport LA
LA Events Coordinator
I believe the float levels are correct....a little trickles out when I shake the car.