ok, next challenge...

now, when i'm at a stop sign or a light my engine dies. i think the idle may be set too low. could that be it or something else?

thoughts?

 

could be a few things, but start with a simple idle adjustment...

when's the last time it was tuned? can you do tune ups yourself? I take it from your post you are not knowledgeable about the car? get a shop manual it'll help you troubleshoot items.

 

Yes, as MiniMad said, it could be several things ... but as a follow-on to your last leaking problem, the float position controls the level of the fuel in the float bowl and also the level in the Jet Assy. Tube; If the leaking fuel around the float bowl helped to control the level, then fixing the leak may have caused the fuel to leak, or overflow somewhere else - namely at the gap between the jet tube and the needle. If there is too much fuel flowing through the jet tube, and your rev's aren't high enough to burn it off (like at idle) then you'll flood the motor. Proper float level adjustment may be all you need ... but a twist of the idle screw may help too (as long as that doesn't screw up your fast idle/choke screw setting ) ...

.... a good info source these days is Burlen Fuel Systems Ltd. - they bought up the names and rights to S.U. (Skinners Union) and make the replacements you'll need - they also have an excellent Workshop Manual and Reference Catalogue for sale through their website that has the best and most accurate information that you would have to gleen from two or three other aftermarket books. You may also want to check Vizard's books "how to modify your mini" and "tuning bl's a-series engine" - virtual Bibles for the Mini Owner.

Have fun with it and if all else fails, we are here to help!

 

if you didn't adj. the float, do so. Does the dashpot have oil in it, & does it move freely? Check point gap if not electronic. Spray wd-40 (propane propellent)where intake manifold meets head & also at carb/manifold gskt (vacuum leaks are idle killers) so check w/wd-40 @throttle shaft. If you have a vacuum adv.distributor,check there by pinching the vacuum hose. Also it could be mixture or timing or valve clearences too tight. So yes it could be many things or a combination of..... If it will idle at 800 rpm then thats probably all it is,but @ 1100-1200 its fine tooth time or mini savy shop.

 

i'm definitely not knowledgable about the car. as i've stated before, i'm learning as i go and loving it. i have the haynes book. i'm going to look into those other books and give it a shot this weekend. otherwise, off to the pros!

 

Is ther an actual **** to adjust the idle or it need to be program at the dealer?

My co-worker MINI died at the traffic light and she took her to the dealer to adjust.

 

My idle is high - currently about 1200 and when the engine is hot it will stick a bit higher 'til I "blip" the throttle. A new throttle cable is on the do list. And I'm pretty sure I'm running rich. I haven't tried to lower the idle as there is no knock or ping in the engine but I was chasing a start problem (that was eventually cured by dumping the POS battery that the car came with and putting in an OPTIMA - I can crank 'til the cows come home now - which is only needed when the engine is very cold and hasn't been run for a week or so)

Poor carb adjustment is probably the reason for my less than desired milage too.

I have the books on order and have resisted tweeking things without a reference. I found the Haynes Reference to be weak regarding the SU carb. (Mini Ref - not the carb specific book). I'm still not sure if I'm supposed to fill the entire pot or just the centre tube with oil & have seen every recommendation from 3 in 1 to 10w30 to maple syrup (just kidding)

UPS says the book should arrive tomorrow so I'll go from there.....

I'm still trying just to determine which carb I have...much less how to rebuild it.

But I still haven't seen anyone say idle should be X RPM for a 1275 with single SU carb....

 

Okeefe, the center tube is all that should be filled, and depending on which version of single carb 1275 you have, the idle should be 650-750 with a fast idle of 1050 (1275 twin carb "S" would be 600/1000).

hope that helps ... of course your 'built' motor with hot cam won't let you idle that slow - those are stock numbers ...

 

O'Keefe,

You mentioned "I was chasing a start problem (that was eventually cured by dumping the POS battery that the car came with and putting in an OPTIMA - I can crank 'til the cows come home now - which is only needed when the engine is very cold and hasn't been run for a week or so)" and I noticed from your pix that you have an Orange '79 - I do too... picked it up last fall

I have mine garaged for the winter here in Ohio and I have "attempted" to start mine occassionally and warm it up. I too have been suffering with a POS battery that I need to replace. It sounds like when your car has not been driven for a while and it is cold out that you have to crank for a while to get it to start. I have the same issue and my battery usually does not hold up long enough for the car to start. I thought that I may have a mechanical fuel pump problem but I haven't gotten my wife to crank while I observe the fuel pump output into a jar. How long do you have to crank to start when its cold and it has been sitting and would you mind giving me the model number information for the battery you purchased?

Its nice not to be the only one learning as I go... I am getting ready to tear mine down to the shell for a rub down, a couple of small repairs and a respray....
Thanks for help and sorry for hijacking the thread! Couldn't resist when I saw issues that reminded me of my own :smile:

Graeme

 

Throw the Haynes books away & get a "Mini Workshop Manual". Once you have one you can walk your self through adjustments, As I said before If you can start a cold engine & drive off without the choke, it's way rich.

 

Oh, but the Haynes is so fun to sit and stare at blankly, then get pissed and start cussing at your car! Heehee.

 

rec'd my copy of 'su carburetters tuning tips & techniques', Brookland Books....after 3 hours I'm still trying to figure out which model SU I have!

damn

 

I PM'd

 

... can you post a picture?

 

most certainly
https://www.northamericanmotoring.co...00&ppuser=3049

 

(STLMINI : sorry about the hi-jack - we'll take this somewhere else if it gets too involved ... )


Okeefe - looks like you have an HIF6 (with the fancy ball-bearing suction chamber on top!) - the "6" is the size (1 + 3/4" throat) and you can measure that to make sure but later models were designated as metric (38 or 44); This was supposed to be an inprovement over the HS series with the floatbowl and jet assembly integrated into the carb body instead of hanging off the side or exposed underneath. It was first used on the expensive cars (re: jaguars) and later adopted for all of everyone's models ...

 

no sweat! i've got the vizard book and it's time for me to get under the bonnet... if it would just stop raining and warm up!

 

Yep - looking a bit more closely at the drawings in the book I dare say you've confirmed it for me. Thanks.

 

ok, so it's not the idle. the idle is set correctly. i think the engine is getting too much fuel and its flooding. is this a setting i can change or do i have a more serious issue?

just to review, the engine starts pretty good. idles around 1000. once the engine is warm i can take off just fine. however, when i stop (or sometimes slow down even) the engine dies. sometimes, it wont start for a few turns after it dies.

 

By set correctly you mean something in the 800 range?

And when you refer to flooding you mean on the restart? I've only seen the term in reference to too much fuel before the engine fires. I have had that happen a few times, if the engine is hot but off for just a few minutes then the restart can be a problem. A few times I've flooded it, evidenced by strong gas smell ... just like my lawn mower.

I'm also taking another look at my fuel lines. I built steel lines because of the proximity to the exhaust manifold, replacing the rubber that was there. But now I wonder if I lost some heat insulation and possibly should go to metalic braid- or re-route as I think I'm geting some vaporization in the line when things are hot.

For your dieing - both book I have say idle too low, and/or too lean. Or float problems.

What's your engine/carb/needle setup?

The Brookland Book (Wade) has a complete setting procedure that matches Haynes. I'll be trying to tone down my idle my next round under the bonnet.

p.s. su carb info links http://www.teglerizer.com/sucarbs/index.html

 

someone in one of these threads suggested that you check for vacume leaks and from the pic of your carb steup you posted in another thread, you may have a few things to investigate there ... BUT it doesn't look too diferent from most Mini engine compartments that work just fine ... a bit of oil and gas mist has coated stuff and turned to grimmy varnish - not that that's a bad thing! ...

... you can check for rich/flooding conditions by pulling a spark plug: if the tip is sooty black (and dry), you may indeed be rich. Chech the float level again - if the float rests too close to the lid, you are too full and the extra gas flows past the jet needle. The jet assembly can also be adjusted upward but you can chech with the piston lift pin (do you know where that is on the underside of the body near the intake?) first: press it just a bit and hold it there (don't press it all the way up) , and the idle will rise a bit and level off there but if it dies, that's too rich .
Now, too rich doesn't always mean floodable, but it is something you can get to ...
... there are several mechanical things you should do before playing with mixture and idle settings: if you haven't had a good tuneup for awhile, get to the rocker gaps first, and the points and advance next, then you can get to the float level and mixture stuff ...


The Mini (and Spridgets and Minors, etc.) is dead simple and Easy to work on - they are Auto Mechanics 101 stuff - applied basic automotive principle embodied in something that's a blast to drive ... taken a step-at-a-time, it's a straight-forward education into cause-and-effect. I hope you are having fun with all these little problems/exercises and not letting them fool you into thinking they are insurmountable - the rewards of a smooth-running Mini are almost as great as the fun in driving it

ok, maybe not but the is a lot of satisfaction in having done it yourself !

 

... and Okeefe may be onto something with the vapour-lock thing in the tube but the stock setup has a steel tube from under the car to the bulkhead and rubber hose the last few inches to the float bowl - and that has always worked well enough; Checking for obstructions (kinks, grit) may be helpful though ... have you noticed any other problems that could indicate starvation (like, problems acceleration up long hills) ?

 

Did you check for air leak at intake and head as I suggested in my 1st post? Its a common stalling cause. Or just tighted nuts holding intake & exhaust manifolds on head. (then check for leak w/WD-40) Idle will get higher if leaking vacuum. Did you check the float level yet with a drill bit ?Yes/No?

 

all the books I have say to exhaust all the potential ignition problems before even thinking about messing with the carb (so now we tell you, right?)

If ignition is not set up properly then messing with the idle and mix is probably going to make a bad situation worse.

Then for real fun you can start searching for a better needle .... did you check out any of the articles on that link?

 

Pulled the plugas and everything was lookin' good - a slight 'bisket' color to the electrodes just like the books say - so I guess my mix is good.

I pulled the top half of the carb off and took it apart. Found a few differences from a HIF6 .... maybe there is a 7 or 8??? Fewer ball bearings in the race than expected, spring is large diameter and hit outside of pot vice hugging the piston, mix adjust is accessed from top, not the side. Nothing major but enought to not be simple mistakes in the books. Things were good - with a bit of gum, especially in the guide slot the piston rides, and the spring. Liberal carb cleaner and a soft brush and paper towels and everything fit back together and seems to move more smoothly.

Idle seemed to have dropped to about 1000, any attempt to drop below that and things get bumpy. Didn't get to drive - raining - but I'm confident!