Sounds good! ... the "6" or "8" would be the size and i think you still have "6" (1-3/4") instead of an "8" (2") throat - but the updates may indicated the metricized version: HIF44 (44 mm throat) with production improvements ...

 

alright, i spent most of sunday trying to figure this out. the result is that the car idles around 900-1000 but 'hunts' between 800 and 1100. it doesn't die as much but still dies. the exhaust no longer spits un-burnt fuel which is good. i didn't even notice that it was doing it until a auto-saavy friend showed me it was doing it (did i mention i was inexperienced at this?)

here's what i have done:

- replaced the spark plugs (old ones were black)
- fixed idle (now idles around 900-1000, but "hunts")
- adjusted jet nut (exhaust used to spew black stuff and now doesn't)
- fixed leaky float chamber (replaced gasket)
- filled dashpot (was rather dry)
- cleaned contacts inside the dist. cap

what i haven't done:
- check for proper float adjustment
- check point gap
- check piston lift pin (can't find it!)
- check float level
- cleaned/checked the jet

some of the stuff above i just can't figure out. some of it i'm too chicken to try. from what i've read, there's quite a few things that could be contributing to this and even if i do the stuff above, i'm not sure it would take care of the issue. i'm pretty sure i'm gonna take it to the shop to have it tuned-up - once i know everything is running right, i think it will be less over-whelming to fix the occasional problem that will come up.

wish i had a garage to work on this thing. it sucks running out of light and chasing clear weather.

 

Have you checked for a vacuum leak? Retighten the manifold to head and carb to manifold bolts. Sometimes the manifold flange gasket leaks and will cause it to hunt....
should use a light oil in dashpot like 3 in 1, etc

On a HIF the piston lift pin is (from the front of the car) on the right side of the carb, between the throttle linkage and the flange to which the air cleaner assembly mounts on the face of the carb throat. It is a small, spring loaded pin which you push up to lift the piston. It leans the mixture.
On older carbs type H its on the opposite side but similar location.

When you lift the pin, the idle ought to increase temporarily, then reduce & start to stumble. That would indicate a proper mixture. If you lift the pin (adding air) and revs increase & stay high, then it is running rich. If you lift the pin and it stumbles immediately or stalls, it is running lean.

 

i can't for the life of me find the piston lift pin - might you have a picture of where it should be? is there a possibility that my carb doesn't have one? in the haynes manual it shows an SU HS2. i wonder if that's what i have? here's a picture. don't mind the arrow.

i worked up the nerve to take the dashpot off and checked the jet needle. it looks really clean and moves freely. after refitting and refilling the dashpot, the car ran a little smoother but still stumbled and died (possible placebo effect?).

i haven't checked for leaks. i'll check my books to see if i can figure where the manifold connects to the carb (slowly learning here.)

 

You do not have an HIF if that's a photo of your carb. It is an HS4, 1 1/2" diameter.. The lifting pin should be on the float bowl side of the carb just forward & above where the bowl attaches.

The carb bolts to the combined intake/exhaust manifold with two nuts (1/2" wrench) . The Manifold bolts to the cylinder head with five nuts same size. There's a gasket at each connection. It is common for the manifold to head gasket to leak or burn out. It is also common for these nuts to loosen. See photo below

Also, check the vacuum lines espcially the one running from the top of the carb to the distributor. Make sure it is connected firmly and has no leaks. The rubber ends often crack & leak. In the picture below its the little black hose line above the fatter hose that connects behind the curved air cleaner mount bracket.

FYI, an HS6 is 1 3/4" throttle diameter and an HIF carb has an integral float chamber below the jet, that is, no side mounted float bowl.

 

well, the car is back from the shop and i'm $250 lighter in the wallet. but the car runs great and has much more power! here's what the expert did:

- removed carb, replaced all gaskets
- cleaned jet feed line and recentered jet (replaced needle/seat assembly)
- removed distributer to repair advance plate, replaced points and condensor
- reset ignition timing and carb settings
- replaced fuel pump with electric pump and regulator

whoooo, was i out of my league!!!!

thanks jeff at j&w automotive! he's the Mini-MAN!

 

No harm in admitting that. I'm about to that point with Jerseygirl's 1800ES. Imagine all of the issues you are having but add 30+ year old electronic fuel injection to the equation... "The sensors Ohm out to specs... so why won't the darn thing run right???" What I wouldn't give for a pair of carbs right now...

I have a week to figure it out before it's first show on May 1.

 

I got my SU carb book & took apart (an HIF-6) and cleaned 'er up good.

Put it back together and was excited that the idle seemed to be happy at a lower rpm ~ 1000, tried racking back to 800. Then I drove it a couple of times. Engine developed a dedency to hunt but only after at least 90 min drive. When the engine is fully hot it doesn't like an idle below 1200.

Given that the only vacume conection is to the advance on the distributor, I'm at a loss. I think that until I find a Mini/Austin savy guy I'll just accept a 1200-1500 idle....car seems really happy there. {1275 Metro with LCB and HIF-6; still with std points and mechanical fuel pump (new in last 6 mo)}

Should I leave well enuf alone?

 

do you have a heat shield between the carby and the inatke manifold protecting the float bowl under the carb from exhuast manifold heat?

 

if you look at the pics in my galley you can see it in the 'starbord side' shot

altho I had the same thought when I saw such a guard on special in the Mini Mania flyer this week

 

I have a Mini with a MG Metro 1275,fast road cam,stage 3 head with 1.5 roller rockers. I only have the 1 3/4 inch single SU. I had the Maniflow LCB ceramic coated to a neaarly chrome finish. I took care of a seriously bad idle problem by just adjusting the timing correctly. I'm sourcing an electronic dizzy today. I'm trying to minimize the potential problems for the drive to the Dragon on Wednesday.
Philthy

 

WHat are you currently running for idle, timing and dwell?

I have a 1275, HIF6 with K&N, & LCB.....I was about to slap on a light but realized I haven't a clue what's 'right'. Haynes has 2 pages of combinations.

As far as the 'ping' test goes ..... I'm right on now.

confused again

Should I replace the distributor innards with electronic?

 

are your settings secret?

Is the question SO dumb?

I'm curious to see the variety out there.....

 

i don't know what the setting are but if i knew them, i would tell you!

mike

 

sorry for not divulging the info you want, O'Keefe, but you haven't given enough information about things llike cam timing and lift, distributor guts (full advance reached when - what springs are on the advance mechanism) ... there are too many variables for anyone to tell you what you need over the phone (yet) - and anyone who tells you they can should be avoided!

The 'ping' test is a good place to start for the equipment currently installed but to get everything working right, you should take a couple of carb needles and a few options for distributor changes to your most trusted Dyno shop and see what works best ... once any one thing is changed from how it left the factory, your own personal machine will then have its own set of setup specs ...