The Ford Barn

Harylufa · 11-03-2013, 08:38 PM

Hi all!

I have a doubt, in my Carb 91-99 power valve has failed, so I installed another alternative carb Holley as spare part.

I noticed that in my 91-99 both idle adjusting screws work fine with one turn.
And installing Holley carb need more than one turn in idle adjusting screw need as three or more turn.

Who of you have this experience?

Thank for reading

Harylufa

Old Henry · 11-03-2013, 09:36 PM

Nothing unusual about the difference in the idle mixture screws. The key is that they work as designed. To adjust them get your engine warmed up and idling smoothly at correct RPMs - 600 RPMs. (My next post explains how to determine correct idle speed without a tachometer.) Then, while engine is idling smoothly turn one of the idle mixture screws in until the engine RPM slows and the engine starts running rough. Then turn that screw out just until the engine runs smooth again. Then repeat on the other idle mixture screw to set it correctly. If screwing the idle mixture screws in all the way doesn't have any effect on the engine then they are not working correctly and may need replaced or there may be an air leak somewhere else that's keeping them from working. Once the idle mixture screws are adjusted as described recheck the idle speed and re-adjust that if necessary.

Old Henry · 11-03-2013, 09:44 PM

To set the correct idle speed of 600 RPM's without a tachometer count the number of times the pump/generator belt goes around in 10 seconds. If it's 25 times that's 600 RPM. If it's more it's too high. If it's less it's too low. Here's a video I made to illustrate: https://www.youtube.com/watch?v=9AH08k0pvdE If your belt does not have a very visible label on it like mine does you may have to put a piece of white tape on it temporarily to count the revolutions.

Harylufa · 11-03-2013, 10:28 PM

Old Henry!

Good video very interesting, I will put in practice. I will back with news.

Thank you

Hary

ken ct · 11-04-2013, 12:52 AM

Way too many turns out.1 turn should be all that's needed. Why not just replace the PV in the 91-99,use a 5.5 and a usa made one. ken ct. usa. Sounds like you have a massive air leak on that Holley.

Harylufa · 11-04-2013, 09:34 AM

Sponsored Links (Register now to hide all advertisements)

Quote:

Originally Posted by ken ct

Way too many turns out.1 turn should be all that's needed. Why not just replace the PV in the 91-99,use a 5.5 and a usa made one. ken ct. usa. Sounds like you have a massive air leak on that Holley.

Hi Ken!

Here where I live not exist the PV 5.5, I must buy it to USA. In 91-99 the PV is 6.5 and other alternative is 4.5 to install.

I will investigate if there is massive air leak.

thank you

Hary

1952henry · 11-04-2013, 05:51 PM

Check with Charlie NY on this site.

11-03-2013, 09:36 PM	#2
Old Henry Senior Member Join Date: Oct 2010 Location: Orem, Utah Posts: 5,762	Re: Carb 94 91-99 vs Holley 94 Nothing unusual about the difference in the idle mixture screws. The key is that they work as designed. To adjust them get your engine warmed up and idling smoothly at correct RPMs - 600 RPMs. (My next post explains how to determine correct idle speed without a tachometer.) Then, while engine is idling smoothly turn one of the idle mixture screws in until the engine RPM slows and the engine starts running rough. Then turn that screw out just until the engine runs smooth again. Then repeat on the other idle mixture screw to set it correctly. If screwing the idle mixture screws in all the way doesn't have any effect on the engine then they are not working correctly and may need replaced or there may be an air leak somewhere else that's keeping them from working. Once the idle mixture screws are adjusted as described recheck the idle speed and re-adjust that if necessary. __________________ Prof. Henry (The Roaming Gnome) "It is good to have an end to journey toward; but it is the journey that matters, in the end.” Ursula K. Le Guin in The Left Hand of Darkness Last edited by Old Henry; 11-04-2013 at 01:21 AM.*

11-03-2013, 09:44 PM	#3
Old Henry Senior Member Join Date: Oct 2010 Location: Orem, Utah Posts: 5,762	Re: Carb 94 91-99 vs Holley 94 To set the correct idle speed of 600 RPM's without a tachometer count the number of times the pump/generator belt goes around in 10 seconds. If it's 25 times that's 600 RPM. If it's more it's too high. If it's less it's too low. Here's a video I made to illustrate: https://www.youtube.com/watch?v=9AH08k0pvdE If your belt does not have a very visible label on it like mine does you may have to put a piece of white tape on it temporarily to count the revolutions. __________________ Prof. Henry (The Roaming Gnome) "It is good to have an end to journey toward; but it is the journey that matters, in the end.” *Ursula K. Le Guin in The Left Hand of Darkness

11-03-2013, 10:28 PM	#4
Harylufa Senior Member Join Date: Dec 2011 Location: Buenos Aires, Argentina! Posts: 356	Re: Carb 94 91-99 vs Holley 94 Old Henry! Good video very interesting, I will put in practice. I will back with news. Thank you Hary __________________ I love my Ford V8 1946! Harylufa!

11-04-2013, 12:52 AM	#5
ken ct BANNED Join Date: May 2010 Location: stratford,ct Posts: 5,971	Re: Carb 94 91-99 vs Holley 94 Way too many turns out.1 turn should be all that's needed. Why not just replace the PV in the 91-99,use a 5.5 and a usa made one. ken ct. usa. Sounds like you have a massive air leak on that Holley.

11-04-2013, 05:51 PM	#7
1952henry Senior Member Join Date: May 2010 Location: North Dakota Posts: 1,618	Re: Carb 94 91-99 vs Holley 94 Check with Charlie NY on this site. __________________ I dig coal, which provides motivation for EVs.