carb questions

[302coupe 10]

Alright so im adjusting my floats and i notice my changes arent having any effect soooo i take a look at the float bowl screw and nut,the nut has no threads??so whats its purpose?well i tried to load pics but photobucket is being pissy.

 

I found the link to the great carb tuning vid ,http://v8tvshow.com/content/view/110/28/

 

Video is GREAT for beginners.

Edited June 10, 2011 by 302coupe

[Rcodenewf 44]

The needle/seat assembly screws into the bowl. The nut has two flats that sit over the needle assembly and is used to raise or lower the floats.

 

There is a little gasket that sits under the nut and on top of the nut so it can seal to the bottom of the screw.

 

With the bowls off and upside down you can roughly set them by turning the nut up or down until the float is level with the bottom (actually top if inverted)...that will get you in the ballpark.

 

Then while idling and warmed up you can raise or lower the needle seat assembly until fuel just trickles out the lower edge of the sight plug on the front and back bowls. I like to set them so nothing comes out until you just give the fender a nudge.

 

You'll need a 5/8 wrench and a flat screwdriver. Hold the nut with the wrench while you crack open the flat screw. You will be turning the nut then to adjust fuel height. Counterclockwise raises the level the opposite to lower.

 

Bear in mind that when attempting to lower the fuel level you will have to loosen one of the lower bowl screws and let some fuel seep out onto a rag as the fuel will stay at the same level probably when the needle is lowered.

 

Be careful if the engine is hot as you do not want to ignite a fire with the leaking fuel. Preferrably let the engine cool before you set the floats...hope this helps.

 

And as suggested above...insist on a genuine Holley kit.

 

Regards....john

[Rcodenewf 44]

The needle/seat assembly screws into the bowl. The nut has two flats that sit over the needle assembly and is used to raise or lower the floats.

 

There is a little gasket that sits under the nut and on top of the nut so it can seal to the bottom of the screw.

 

With the bowls off and upside down you can roughly set them by turning the nut up or down until the float is level with the bottom (actually top if inverted)...that will get you in the ballpark.

 

Then while idling and warmed up you can raise or lower the needle seat assembly until fuel just trickles out the lower edge of the sight plug on the front and back bowls. I like to set them so nothing comes out until you just give the fender a nudge.

 

You'll need a 5/8 wrench and a flat screwdriver. Hold the nut with the wrench while you crack open the flat screw. You will be turning the nut then to adjust fuel height. Counterclockwise raises the level the opposite to lower.

 

Bear in mind that when attempting to lower the fuel level you will have to loosen one of the lower bowl screws and let some fuel seep out onto a rag as the fuel will stay at the same level probably when the needle is lowered.

 

Be careful if the engine is hot as you do not want to ignite a fire with the leaking fuel. Preferrably let the engine cool before you set the floats...hope this helps.

 

And as suggested above...insist on a genuine Holley kit.

 

Regards....john

[ashleesmach1 28]

this an awesome website thanks for the link!!!!!:rockon:

 

 

 

 

Alright so im adjusting my floats and i notice my changes arent having any effect soooo i take a look at the float bowl screw and nut,the nut has no threads??so whats its purpose?well i tried to load pics but photobucket is being pissy.

 

I found the link to the great carb tuning vid ,http://v8tvshow.com/content/view/110/28/

 

Video is GREAT for beginners.

[ashleesmach1 28]

this an awesome website thanks for the link!!!!!:rockon:

 

 

 

 

Alright so im adjusting my floats and i notice my changes arent having any effect soooo i take a look at the float bowl screw and nut,the nut has no threads??so whats its purpose?well i tried to load pics but photobucket is being pissy.

 

I found the link to the great carb tuning vid ,http://v8tvshow.com/content/view/110/28/

 

Video is GREAT for beginners.

[302coupe 10]

Appreciate the advice Rcode,but with as many times as ive watched vids on carbs i think ive memorised how to tune mine.The nut under the screw just doesnt have thread so it cant be used to lower or heighten the screw/floats.I tried to explain this to a buddy of mine who knows my car and even he just kept telling me what Rcode is telling me.

 

Ive watched the video above about 10 times and everytime the guy says loosen the nut ,but mine doesnt need loosening,it just turns freely.It does have the two gasket kinda rubber washers attached on both sides tho.I plan on bringing the car to a guy i nkow later today to show him what i mean.

[302coupe 10]

Appreciate the advice Rcode,but with as many times as ive watched vids on carbs i think ive memorised how to tune mine.The nut under the screw just doesnt have thread so it cant be used to lower or heighten the screw/floats.I tried to explain this to a buddy of mine who knows my car and even he just kept telling me what Rcode is telling me.

 

Ive watched the video above about 10 times and everytime the guy says loosen the nut ,but mine doesnt need loosening,it just turns freely.It does have the two gasket kinda rubber washers attached on both sides tho.I plan on bringing the car to a guy i nkow later today to show him what i mean.

[LoneWolf2U 136]

Remove the screw and nut.

you will see the needles adjusting housing has been screwed in too far.

you need to backout the housing so adjusting is possiable.

Having the needle housing too far down will cause float to stick needle when it fills causing it to over flow or no fuel delivered.

[LoneWolf2U 136]

Remove the screw and nut.

you will see the needles adjusting housing has been screwed in too far.

you need to backout the housing so adjusting is possiable.

Having the needle housing too far down will cause float to stick needle when it fills causing it to over flow or no fuel delivered.

[302coupe 10]

Makes sense,the "housing" only had about 3 threads thickness BUT adjust the housing is still useless cause the lock nut doesnt lock hehe,it doesnt have any thread.I keep explaining this to people and i feel like an idiot cause maybe im missing the absolute obvious.

 

Im just gonna take the housing out and head over to home depot and look for a proper nut.Im convinced this is the root of all my problems,if the primary bowl isnt filiing with enough fuel its not wonder my car boggs when i push the pedal a bit but flys when i push it to the floor,cause thats activating my secondaries right?

Edited June 10, 2011 by 302coupe

[302coupe 10]

Makes sense,the "housing" only had about 3 threads thickness BUT adjust the housing is still useless cause the lock nut doesnt lock hehe,it doesnt have any thread.I keep explaining this to people and i feel like an idiot cause maybe im missing the absolute obvious.

 

Im just gonna take the housing out and head over to home depot and look for a proper nut.Im convinced this is the root of all my problems,if the primary bowl isnt filiing with enough fuel its not wonder my car boggs when i push the pedal a bit but flys when i push it to the floor,cause thats activating my secondaries right?

Edited June 10, 2011 by 302coupe

[LoneWolf2U 136]

Umm... The nut has no threads, Yep it is just the part that turns the housing for adjusting.

Look at the housing and nut, Both have a flat areas that match up.

The screw and washers make the sealing/locking for the nut and housing.

[LoneWolf2U 136]

Umm... The nut has no threads, Yep it is just the part that turns the housing for adjusting.

Look at the housing and nut, Both have a flat areas that match up.

The screw and washers make the sealing/locking for the nut and housing.

[302coupe 10]

Awww,i see.Yup i thought there was something obvious i was missing.I still think that nut isnt moving the housing cause i dont have to line up the nut and housing for the nut to slide down over the housing but ill check that when i get home.

[302coupe 10]

Awww,i see.Yup i thought there was something obvious i was missing.I still think that nut isnt moving the housing cause i dont have to line up the nut and housing for the nut to slide down over the housing but ill check that when i get home.

[jholmes217 65]

Another thing to consider is a 650 double pumper may be too much for your engine. From your signature, I see you have a 302 cubic inch engine with a edelbrock performer RPM intake and a Holley 650 Double pumper with a 4spd top loader. What else is done to the engine?

My last 302 that I built back in the late 80's had a 600 double pumper, and it still ran a little rich. That build was a stock 302 with a Eddy intake, dual point dizzy, headers, and a mild cam (don't remember the make or grind now.) Compression was about 9.5 to 1, and heads were not "shaved" or milled to increase compression.

Edited June 10, 2011 by jholmes217

[jholmes217 65]

Another thing to consider is a 650 double pumper may be too much for your engine. From your signature, I see you have a 302 cubic inch engine with a edelbrock performer RPM intake and a Holley 650 Double pumper with a 4spd top loader. What else is done to the engine?

My last 302 that I built back in the late 80's had a 600 double pumper, and it still ran a little rich. That build was a stock 302 with a Eddy intake, dual point dizzy, headers, and a mild cam (don't remember the make or grind now.) Compression was about 9.5 to 1, and heads were not "shaved" or milled to increase compression.

Edited June 10, 2011 by jholmes217

[302coupe 10]

Update:Spent the weekend tunign carb and removing/cleaning/painting and re-installing my z bar.Mach1,you were right about that nut,i just had it screwed in way to low for the nut to catch on the flat sides.So i got it running pretty good and decide to take a test drive,runns super well until i get to a stop after getting off the highway.

 

Car dies and barely wants to start again,did this all the way home.Get home and open the hood to find my carb and intake soaked with gas,WTF?So start re-tuning the carb and canot get the fuel level down in the bowls,im thinkng floats are stuck so i tap the carb with a hammer,try everything i can think off and still the car will barely start and wont idle at all.Guess ill be taking the bowls off tonight.any suggestions appreciated.

 

Jholmes:My 302 is definetly built up,with what ,im not sure yet,im still trying to decipher the terrible handwritting of the bills for parts on my engine.

Edited June 13, 2011 by 302coupe

[302coupe 10]

Update:Spent the weekend tunign carb and removing/cleaning/painting and re-installing my z bar.Mach1,you were right about that nut,i just had it screwed in way to low for the nut to catch on the flat sides.So i got it running pretty good and decide to take a test drive,runns super well until i get to a stop after getting off the highway.

 

Car dies and barely wants to start again,did this all the way home.Get home and open the hood to find my carb and intake soaked with gas,WTF?So start re-tuning the carb and canot get the fuel level down in the bowls,im thinkng floats are stuck so i tap the carb with a hammer,try everything i can think off and still the car will barely start and wont idle at all.Guess ill be taking the bowls off tonight.any suggestions appreciated.

 

Jholmes:My 302 is definetly built up,with what ,im not sure yet,im still trying to decipher the terrible handwritting of the bills for parts on my engine.

Edited June 13, 2011 by 302coupe

[jholmes217 65]

Update:Spent the weekend tunign carb and removing/cleaning/painting and re-installing my z bar.Mach1,you were right about that nut,i just had it screwed in way to low for the nut to catch on the flat sides.So i got it running pretty good and decide to take a test drive,runns super well until i get to a stop after getting off the highway.

 

Car dies and barely wants to start again,did this all the way home.Get home and open the hood to find my carb and intake soaked with gas,WTF?So start re-tuning the carb and canot get the fuel level down in the bowls,im thinkng floats are stuck so i tap the carb with a hammer,try everything i can think off and still the car will barely start and wont idle at all.Guess ill be taking the bowls off tonight.any suggestions appreciated.

If your carb and intake are covered in gas, then you have a leak somewhere. 1st step IMO is take the floats out and put them in parts cleaner or gas (hold them under) and see if they take on fluid. If they do, they need replaced. After you put the carb back together, check for leaks and fix any leaks you find. Then, tune for idle, then test drive. What kind of fuel pump is on the car? If you have a high pressure pump, you may need a regulator. If your pressure is higher than 6, you need a regulator in my opinion.

Edited June 13, 2011 by jholmes217
fat finger typo

[jholmes217 65]

Update:Spent the weekend tunign carb and removing/cleaning/painting and re-installing my z bar.Mach1,you were right about that nut,i just had it screwed in way to low for the nut to catch on the flat sides.So i got it running pretty good and decide to take a test drive,runns super well until i get to a stop after getting off the highway.

 

Car dies and barely wants to start again,did this all the way home.Get home and open the hood to find my carb and intake soaked with gas,WTF?So start re-tuning the carb and canot get the fuel level down in the bowls,im thinkng floats are stuck so i tap the carb with a hammer,try everything i can think off and still the car will barely start and wont idle at all.Guess ill be taking the bowls off tonight.any suggestions appreciated.

If your carb and intake are covered in gas, then you have a leak somewhere. 1st step IMO is take the floats out and put them in parts cleaner or gas (hold them under) and see if they take on fluid. If they do, they need replaced. After you put the carb back together, check for leaks and fix any leaks you find. Then, tune for idle, then test drive. What kind of fuel pump is on the car? If you have a high pressure pump, you may need a regulator. If your pressure is higher than 6, you need a regulator in my opinion.

Edited June 13, 2011 by jholmes217
fat finger typo

[302coupe 10]

My pressure ia about 7.5/8 ish.Im pretty sure my floats are sticking for some reason,just cant figure out why.I say this because when i unscrew the side screws to check the fuel level,gas just pours out and i cant get it to come down no matter how far in i screw the bowl nut.

[302coupe 10]

My pressure ia about 7.5/8 ish.Im pretty sure my floats are sticking for some reason,just cant figure out why.I say this because when i unscrew the side screws to check the fuel level,gas just pours out and i cant get it to come down no matter how far in i screw the bowl nut.

[LoneWolf2U 136]

Its from having them screwed in too far. It will cause the needles to bind and flood the carb/intake.

 

First take the bowls off and inspect the floats and needles.

When you reinstall the needle seats the shell should be approx .002-.005 below the adjusting nut for starting point on float adjustments.

Now with the bowls upsidedown look at where the float is, Does it sit level?

Yes, then it will adjust with nut. No? then you need to adjust the floats needle tang till it sits level before installing it back onto the carb or you will have trouble getting the fuel level correct.

If the floats you have are the ones with a small bump where the needle rides, you have to bend the floats arm till it sits level.

Next Holleys do not like over 6 psi of fuel pressure as it will over ride the floats.

Edited June 13, 2011 by Mach1Rider

[LoneWolf2U 136]

Its from having them screwed in too far. It will cause the needles to bind and flood the carb/intake.

 

First take the bowls off and inspect the floats and needles.

When you reinstall the needle seats the shell should be approx .002-.005 below the adjusting nut for starting point on float adjustments.

Now with the bowls upsidedown look at where the float is, Does it sit level?

Yes, then it will adjust with nut. No? then you need to adjust the floats needle tang till it sits level before installing it back onto the carb or you will have trouble getting the fuel level correct.

If the floats you have are the ones with a small bump where the needle rides, you have to bend the floats arm till it sits level.

Next Holleys do not like over 6 psi of fuel pressure as it will over ride the floats.

Edited June 13, 2011 by Mach1Rider