× 1-800-946-2642 Home My Account Social / Forum Articles Contact My Cart
Shop Now
Select Your Car Type Sale Items Clearance Items New Items
   Forum Width:     Forum Type: 

 Posted: Aug 21, 2018 05:08AM
Total posts: 8382
Last post: Jan 13, 2022
Member since:Feb 7, 2006
Cars in Garage: 0
Photos: 0
WorkBench Posts: 0
Quote:
Originally Posted by MrFocus
Quote:
Originally Posted by dklawson
Quote:
Originally Posted by MrFocus
 
The inner o-ring was pretty much useless. Flattened and tore like paper. So ive been poking around trying to find a new o-ring and I am constantly second guessing myself. 
Don't over think this.  If you have a set of calipers, measure the OD of the part the o-ring sits on (that will be the o-ring's nominal ID).  Then measure ID of the hole the o-ring goes in (that will be the o-ring's nominal OD.  For both the ID and OD take measurements at several points and average them.

Now go to the McMaster.com website and search for "o-rings".  When you look up o-ring sizes try to stay with the common AS568A series.  Find a Buna-N or Viton o-ring that is slightly smaller in ID than your measurement and slightly larger in OD.  Write down the AS568A number that sort of matches your measurements.  The AS568A number will be a 3 digits.  Write that down and go to the local parts store.  Tell them that's what you need in Buna-N or Viton.  Do not get EPDM or Neoprene.  
Ill do that this evening! You are totally correct though i was way overthinking it. I work with aircraft so maybe the o rings with cross reference. Ill cross my fingers!
Try Joe Curto in NY 718 762 7878 he stocks, repairs and rebuilds all SU products.

If in doubt, flat out. Colin Mc Rae MBE 1968-2007.

Give a car more power and it goes faster on the straights,
make a car lighter and it's faster everywhere. Colin Chapman.

 Posted: Aug 20, 2018 02:44PM
Total posts: 93
Last post: Mar 3, 2020
Member since:Dec 16, 2009
Cars in Garage: 0
Photos: 0
WorkBench Posts: 0
I heard from someone that the Harbor Freight O rings work but i would be sceptical of how long they last.

 Posted: Aug 20, 2018 05:19AM
Total posts: 7
Last post: Dec 6, 2018
Member since:Dec 23, 2017
Cars in Garage: 0
Photos: 0
WorkBench Posts: 0
Quote:
Originally Posted by dklawson
Quote:
Originally Posted by MrFocus
 
The inner o-ring was pretty much useless. Flattened and tore like paper. So ive been poking around trying to find a new o-ring and I am constantly second guessing myself. 
Don't over think this.  If you have a set of calipers, measure the OD of the part the o-ring sits on (that will be the o-ring's nominal ID).  Then measure ID of the hole the o-ring goes in (that will be the o-ring's nominal OD.  For both the ID and OD take measurements at several points and average them.

Now go to the McMaster.com website and search for "o-rings".  When you look up o-ring sizes try to stay with the common AS568A series.  Find a Buna-N or Viton o-ring that is slightly smaller in ID than your measurement and slightly larger in OD.  Write down the AS568A number that sort of matches your measurements.  The AS568A number will be a 3 digits.  Write that down and go to the local parts store.  Tell them that's what you need in Buna-N or Viton.  Do not get EPDM or Neoprene.  
Ill do that this evening! You are totally correct though i was way overthinking it. I work with aircraft so maybe the o rings with cross reference. Ill cross my fingers!

 Posted: Aug 20, 2018 05:04AM
Total posts: 9241
Last post: Aug 17, 2023
Member since:Jun 5, 2000
Cars in Garage: 0
Photos: 0
WorkBench Posts: 0
US
Quote:
Originally Posted by MrFocus
 
The inner o-ring was pretty much useless. Flattened and tore like paper. So ive been poking around trying to find a new o-ring and I am constantly second guessing myself. 
Don't over think this.  If you have a set of calipers, measure the OD of the part the o-ring sits on (that will be the o-ring's nominal ID).  Then measure ID of the hole the o-ring goes in (that will be the o-ring's nominal OD.  For both the ID and OD take measurements at several points and average them.

Now go to the McMaster.com website and search for "o-rings".  When you look up o-ring sizes try to stay with the common AS568A series.  Find a Buna-N or Viton o-ring that is slightly smaller in ID than your measurement and slightly larger in OD.  Write down the AS568A number that sort of matches your measurements.  The AS568A number will be a 3 digits.  Write that down and go to the local parts store.  Tell them that's what you need in Buna-N or Viton.  Do not get EPDM or Neoprene.  

Doug L.
 Posted: Aug 20, 2018 04:35AM
Total posts: 9528
Last post: Mar 27, 2024
Member since:Aug 14, 2002
Cars in Garage: 0
Photos: 0
WorkBench Posts: 0
CA
"Stevejohn" appears to be the scammer of the day.

.

"Hang on a minute lads....I've got a great idea."

 Posted: Aug 19, 2018 06:25PM
Total posts: 7
Last post: Dec 6, 2018
Member since:Dec 23, 2017
Cars in Garage: 0
Photos: 0
WorkBench Posts: 0
Quote:
Originally Posted by malsal
Also check the choke o ring seals when they go bad the carb will run rich constantly.
Another thing make sure the engine is in good tune before attempting to set the carb. This includes setting points(if equipped), setting plugs, setting valves, setting timing, you are wasting your time if these settings are not correct before you start to set the carb.
The inner o-ring was pretty much useless. Flattened and tore like paper. So ive been poking around trying to find a new o-ring and I am constantly second guessing myself. I can seam to find a part number for the seal and the kits listed pretty much everywhere dont have the seal part number listed either. The first link is the o ring I need the second is the cheapest kit I have found.

https://www.scparts.co.uk/sc_en/british-cars/mini/mini-1959-2000/carburettor-injection-and-air-filter/su-hif44-internal-carburettor/o-ring-84611.html

https://www.minimania.com/part/WZX1505/Classic-Mini-Hif6-hif44-Gasket-And-Seal-Kit

 Posted: Aug 19, 2018 08:19AM
Total posts: 8382
Last post: Jan 13, 2022
Member since:Feb 7, 2006
Cars in Garage: 0
Photos: 0
WorkBench Posts: 0
Also check the choke o ring seals when they go bad the carb will run rich constantly.
Another thing make sure the engine is in good tune before attempting to set the carb. This includes setting points(if equipped), setting plugs, setting valves, setting timing, you are wasting your time if these settings are not correct before you start to set the carb.

If in doubt, flat out. Colin Mc Rae MBE 1968-2007.

Give a car more power and it goes faster on the straights,
make a car lighter and it's faster everywhere. Colin Chapman.

 Posted: Aug 19, 2018 07:20AM
 Edited:  Aug 19, 2018 07:28AM
Total posts: 9241
Last post: Aug 17, 2023
Member since:Jun 5, 2000
Cars in Garage: 0
Photos: 0
WorkBench Posts: 0
US
Jet above the bridge?  Not good.  Since the car is relatively new to you, make sure the jet inside diameter corresponds correctly with the largest diameter on the needle.  There are 0.100" jets and 0.090" jets (at least for HS series carbs... I assume this also applies for HIF).  The needle should almost close the diameter of the jet off if inserted fully.

If you remove the vacuum chamber/piston/needle and turn the engine over a few times, how high is the fuel in the jet?  Is the fuel coming out of the jet or below the top of the jet.  If the fuel is coming out of the jet, work with the float valve to make sure it is set appropriately.  If the fuel is below the top of the jet, put the carb back together after setting the jet flush with the bridge and adjust DOWN from there.  At the same time make sure the needle is correctly installed in the piston.  

If the engine refuses to work with that as a starting point you should probably consider a different needle.

When you say the dashpot is out of oil... what are you expecting and seeing?  The oil doesn't come all the way to the top of the threaded hole.  When you put the oil in, fill until the oil is about 1/4" below the top of the innermost steel tube... the tube that the brass dashpot fits inside of.  If you fill over the top of the innermost steel tube, that oil will get sucked into the carb and burned.  That's not a problem... but you'll notice the oil level always ends up where it needs to be, 1/4" below the top of the tube.

EDIT:  The forum editor is not letting me insert the image directly and wants the link to be secure to display a URL linked picture.  Geeze.  Sorry, cut and paste the address below WITHOUT the HTTPS prefix and you will see a picture of the dashpot oil level.

//www.mgbimages.uk.gridhosted.co.uk/images/sudamper1.jpg

Doug L.
 Posted: Aug 18, 2018 02:42PM
Total posts: 7
Last post: Dec 6, 2018
Member since:Dec 23, 2017
Cars in Garage: 0
Photos: 0
WorkBench Posts: 0
I pulled the carb. The jet is in fact moving. And was 4 turns above the venturi bridge. The dashpot was out of oil again. Any idears?

 Posted: Aug 18, 2018 12:50PM
Total posts: 7
Last post: Dec 6, 2018
Member since:Dec 23, 2017
Cars in Garage: 0
Photos: 0
WorkBench Posts: 0
Quote:
Originally Posted by Dan Moffet
Quote:
Originally Posted by MrFocus
I believe so. It is the bfy needle. When adjusting the carburetor back in June I had the idle around 800 and then it's at 4 months and when I went to drive it the idle is around 1800.. and on top of the idle being too high anytime I give it tiny bit of acceleration the motor tries to die
Assuming the needle is not far off, I'd suspect the dashpot needs oil. Maybe it is low or has the wrong oil in it. In a SU carb, the dashpot acts as an accelerator pump but not as you would suspect. During normal steady-state speed, the intake vacuum lifts and holds the dashpot piston and the needle, providing the right amount of fuel in relation to the amount of air the throttle is letting in. When you try to accelerate, the dashpot damper (with the oil) delays the lifting of the dashpot piston. This holds the bottom of the piston close to the 'bridge' and the tip of the main jet. This forces the air coming in to pass through a narrow slit at higher velocity, which sucks extra hard on the tip of the jet, pulling extra fuel in but limiting the amount of additional air at the same time. The effect is like a temporary choke application instead of an accelerator pump squirt.
With no oil or a too light oil, the dashpot piston rises too soon, you get a temporary lean-out condition and the hesitation.

That is one thing I paid it particular attention to cuz everything I read said how important it was that had oil and the correct oil. When I dismantled it the first time it did not have any oil so I put the general purpose oil that is recommended I can't exactly remember the weight. Is there a seal that keeps that the oil in the dash pot from leaking into the carburetor Barrel?

 Posted: Aug 18, 2018 08:46AM
Total posts: 9528
Last post: Mar 27, 2024
Member since:Aug 14, 2002
Cars in Garage: 0
Photos: 0
WorkBench Posts: 0
CA
Quote:
Originally Posted by MrFocus
I believe so. It is the bfy needle. When adjusting the carburetor back in June I had the idle around 800 and then it's at 4 months and when I went to drive it the idle is around 1800.. and on top of the idle being too high anytime I give it tiny bit of acceleration the motor tries to die
Assuming the needle is not far off, I'd suspect the dashpot needs oil. Maybe it is low or has the wrong oil in it. In a SU carb, the dashpot acts as an accelerator pump but not as you would suspect. During normal steady-state speed, the intake vacuum lifts and holds the dashpot piston and the needle, providing the right amount of fuel in relation to the amount of air the throttle is letting in. When you try to accelerate, the dashpot damper (with the oil) delays the lifting of the dashpot piston. This holds the bottom of the piston close to the 'bridge' and the tip of the main jet. This forces the air coming in to pass through a narrow slit at higher velocity, which sucks extra hard on the tip of the jet, pulling extra fuel in but limiting the amount of additional air at the same time. The effect is like a temporary choke application instead of an accelerator pump squirt.
With no oil or a too light oil, the dashpot piston rises too soon, you get a temporary lean-out condition and the hesitation.

.

"Hang on a minute lads....I've got a great idea."

 Posted: Aug 18, 2018 08:11AM
Total posts: 371
Last post: Apr 20, 2023
Member since:Sep 6, 2015
Cars in Garage: 0
Photos: 0
WorkBench Posts: 0
Checking the mixture with plug color is not very accurate.  The time you drive it back to your garage will dis-color the plugs normal speed color, which you are probably tuning for.  An exhaust gas analyzer is more accurate.

 Posted: Aug 18, 2018 07:39AM
Total posts: 7
Last post: Dec 6, 2018
Member since:Dec 23, 2017
Cars in Garage: 0
Photos: 0
WorkBench Posts: 0
I believe so. It is the bfy needle. When adjusting the carburetor back in June I had the idle around 800 and then it's at 4 months and when I went to drive it the idle is around 1800.. and on top of the idle being too high anytime I give it tiny bit of acceleration the motor tries to die

 Posted: Aug 18, 2018 06:25AM
Total posts: 9528
Last post: Mar 27, 2024
Member since:Aug 14, 2002
Cars in Garage: 0
Photos: 0
WorkBench Posts: 0
CA
By turning the mixture adjustment screw the correct direction I assume you mean counter-clockwise to lean out the mixture.
You can check that the jet is moving when you turn the screw if you remove the dashpot and observe the top of the jet.
Another thing to check is the choke mechanism is working properly. The "choke" is actually a secondary fuel passage to provide extra fuel for starting and warm-up. If the choke isn't coming 'off' fully or if its internal seals (it is a valve) are worn or damaged, you will get too much fuel.

A big issue with HIF carbs is that they have a bi-metallic lever between the screw and the jet. Its purpose is to richen the mixture a little when the engine is cold, to improve drivability and lean it out once the engine is warmed up.. The intention is to set the mixture with the engine warmed up. The problem is that if you are doing it in your garage or driveway, there is no air passing through the engine bay and the heat rising from the manifold continues to heat the carb and the bi-metallic piece continues to get hotter and flex more, leaning out the mixture as you are trying to set it. I don't know how to overcome this, except by a huge fan to simulate a moving car. I could never get it right. I made a non-bimetallic version of the lever from stainless steel and never looked back.

.

"Hang on a minute lads....I've got a great idea."

 Posted: Aug 17, 2018 06:55PM
 Edited:  Aug 17, 2018 06:56PM
Total posts: 1716
Last post: Oct 18, 2020
Member since:Oct 18, 2011
Cars in Garage: 0
Photos: 0
WorkBench Posts: 0
You do have the correct needle??? And with unleaded fuel you're not going to get much variation in plug colours until you get to the extremes..

All needles are pretty much the same at idle ..but as soon as you  start to drive ????

Cheers, Ian

 Posted: Aug 17, 2018 02:41PM
 Edited:  Aug 17, 2018 04:06PM
Total posts: 7
Last post: Dec 6, 2018
Member since:Dec 23, 2017
Cars in Garage: 0
Photos: 0
WorkBench Posts: 0
So I just bought my 84 Austin Mini 1275 in April and I have been messing around with setting the carb for a while. I adjusted the air/fuel screw imo a crap ton and it seems to not have any effect on the carb. The Carb is  a HIF44. It is running very rich. During initial adjustments I would make the adjustment drive it for about 10 minutes then check my plug. I did turn the adjustment screw the correct direction. 

What are some methods i can do to confirm the adjustment is working. I plan on tearing the carb back down and reseting it per the overhaul instructions from the haynes manual.

Thank you in advance!