37 replies to this topic

[imack]

What plugs are you running? Heat range correct?

[johnR]

AAU is leaner than a AAC needle. The engine will run on an AAU (I have one fitted along with a stage one kit to my 998 and 1275)

I use engine oil in the carb Dashpot on all my minis and they all run slightly rich but are set to the emission limits for the year of car.

When you fit the needle the flange on the needle (where the spring sits) needs to be flush with the base of the dashpot.

There are two jet sizes and thus two needle diameters.

Hope this helps

I think you mean that the step on the needle needs to be level with the bottom of the piston? - although we may be talking about different types of needles?

Edited by johnR, 19 June 2019 - 09:40 AM.

[cal844]

AAU is leaner than a AAC needle. The engine will run on an AAU (I have one fitted along with a stage one kit to my 998 and 1275)

I use engine oil in the carb Dashpot on all my minis and they all run slightly rich but are set to the emission limits for the year of car.

When you fit the needle the flange on the needle (where the spring sits) needs to be flush with the base of the dashpot.

There are two jet sizes and thus two needle diameters.

Hope this helps

I think you mean that the step on the needle needs to be level with the bottom of the piston? - although we may be talking about different types of needles?

I will post a picture of my HS4 carb soon and how I have it set. I believe you may have worded it better than me, but a picture or two will help.

As for fitting the HIF carb it won't fit to a pre 1990 car. The 1990 onwards engines are 1/2 an inch forward in the subframe

Edited by cal844, 19 June 2019 - 09:47 AM.

[cal844]

Pictures of how I set my needles up into the piston.





Yes I know the collar might be upside down but it prevents the needle dropping from the set height

[mini-mad-mark]

Thanks again for taking the time to read my drivel and offering ideas

 

OK well the needle in the piston set up -  we are all doing the same just wording it differently. Spring onto flange,  needle into adaptor/collar (?), collar flush to bottom of piston. 

Thanks for the pic to explain as I don't have mine out ATM

 

Plugs are NGK BP6ES (OK for std and stg 1 and beyond that even from what I read)

 

I have tried most things one at a time to isolate the issue (except when I first did plugs, leads and cap together and then points, condenser and rotor arm together - logical things to do together normally?)

 

Then its been one step at a time - i think this is the order so far but its been going on for a bit so I may have them in the wrong order or missed one or two

 

-Change coil for new ballast coil

-Change coil for good std with 12v feed

-Change back to ballast coil 

-Added additional engine earth lead

Up to this point I was convinced it was an ignition issue but then as that was all good (or ought to be by now) I started on the fuelling side

 

-Check valve clearances

-Change needle from AAA back to std AAC

-Check valve clearances again (doubted myself but they were correct)

-Change carb for believed good carb (was running OK on engine it was removed from)

-Change carb back to original

-Change new condenser for a used one from working dizzy (as heard that there are duff ones) then changed back to new one

-Change head gasket/check valve seating (and of course redo valve clearances!!!)

-Change needle valve for one which was perfect (although the other one was working ok until this issue and not bad) and check float height/level

-Check fuel not entering jet/carb under pressure without vacuum

-Adjust mixture to absolute leanest setting and back to normal again (15 flats out) and every single flat in between that

-Try std coil/12v feed again just in case and went back to the new ballast coil.

-Run without air filter (and with it back on again)

-Change plugs again (as taking the point that they might be fubed by the constant bad running - and I will get another spare set just in case these are now knackered)

 

It ran fractionally better after the last step until the plugs got fouled so when I got back to my house and restarted it was bogged again.

 

In between each stage test run quite fast/hard and not too much idling (so shouldn't be idling to cause the fouling) until it bogged out and would barely pull third gear then I would go home and sulk   (and then clean the plugs and try again until the last plug change - haven't cleaned them yet as I packed up in disgust)

 

 

I don't give in easily but this has done me I think - will try a new jet and needle but then I am done.

 

My wife knows I am getting a bit to the end of my tether as she said I could buy a new engine if necessary    but I explained that this has only done around 35K and ts not the engine at fault (well I don't think so but....) 

 

It must be something obvious that I am doing wrong but I never had a problem that I couldn't fix with one or other (or more than one sometimes) of the things mentioned.

(Usually adjusting the carb or replacing some/several ingnition parts did the trick for most bad running I ever had  or at worst a head gasket - never had that many to be honest)

 

I mentioned in one post about me driving my project from Taunton to Northampton with the head gasket gone - even that didn't run as bad as this???

 

I guess I might have exhausted everyone on here with my ramblings...but thanks in advance

 

Is there anyone recommended near to Northampton who could diagnose scientifically (and fix it)  rather than as I am by trial and error; its not easy as I can barely drive the car above 25 mph so not easy to get it anywhere unless I pay someone to trailer it for me. (Starting to seriously think about the idea as I am pretty much cheesed off with it)

 

Cheers

[mini-mad-mark]

I know people like to hear when issues are solved and what the solution was. Well the problem seems solved (need more run time before I am totally confident) and I know what I did but I can't explain the solution.

 

A mate of mine came round this afternoon to put a fresh pair of eyes on the issue. Even he was surprised by just how much soot there was on the plugs 

 

With no other ideas springing to mind after  going through most of what I already tried we did the only thing I hadn't done which was to change the jet housing and jet from the spare carb into the original carb - shouldn't have made any difference as I had previously tried the spare carb complete which made no difference then.

 

It ran too lean to start with and I had to pull the choke out to get it to pull away (a good sign straight off) - I put the Stg1 needle back in which seems to have cured that. 

 

Pulling the plugs shows them to be pretty clean, maybe a little lean, but only did half a dozen miles (which was previously enough to cause the soot) 

 

No idea why it worked other than I must have done something so blindingly obviously wrong or stupid that I couldn't see it and doing the jet change fixed it....?

 

Cheers for the support/help and sorry I can't give a definitive answer (which is frustrating as I don't know why it worked)

[cal844]

Did you fit the dashpot spring and use the same grade of oil in the dashpot.

My clubman estate carb didn't have the spring fitted. The carb had been on a 998 that was in the car when I bought it... I'd fitted it to the 1275cc replacement engine without taking the piston out of the housing...

It wasn't until I took the above pictures I realised there was no spring fitted.

The car had been plagued with an issue where I'd be driving perfect then come to a set of lights and it would die... starts right back up too

So worth checking ?

[mini-mad-mark]

Yep same spring and same oil (Mini Spares 20/50)

 

No idea how or why but to be honest just happy its running properly

 

Cheers again to all for the suggestions

[cal844]

Glad it's sorted,now to do some miles and enjoy leaving Imprezas etc in the twisty stuff

[mini-mad-mark]

Not fixed..... a blindingly obvious/stupid mistake this time.

I forgot to reattach the vac advance hose so I was bleeding air in hence the slight lean and slight hesitance pulling away.

 

Reconnecting it has put me back to square one with soot again.....

 

At least it confirms that the last change was not a fix (I couldnt understand why it would be and turns out it didn't of course)

 

However the better running with the vac disconnected (a bit lean maybe) at least tells me it is definitely fuel related and not electrical

 

Will try a new jet to take out the waxstat and then might look for a recon carb and see whether that works.

 

Alternative is to run with the vac hose off to at least be able to drive it somewhere that can diagnose/fix it (not a long term solution I realise)

Any suggestions close to Northampton that could help me.

 

Cheers, Mark

[cal844]

Try Northampton motorsport. They'll dyno anything.

Www.northamptonmotorsport.com

[mini-mad-mark]

Onto plan c (or d, e, f, z,  who knows?)

 

Got a buddy of mine to come round and bring his carb from a well running motor.

 

It seems to have worked, and he is taking his car off the road for a complete rebuild so he said I can hang on to the carb for the foreseeable....

 

Remembered to fit the vac advance pipe this time (!) so hopefully this IS a fix.

 

However the frustrating thing is that I still can't see that I did anything wrong with the original carb/needle change so still a bit peeved (but happy if it continues to run properly of course)

 

Watch this space......

[cal844]

Copy all the settings off his carb and get yours rebuilt with new bushes

[Zami]

25 yrs ago during my first rebuild I had the same issue as you experienced. In the process of trouble shooting I pulled the dash pot off one of the HS4s but left the piston with needle in position. I made sure the needle was properly fitted. I turned on the ignition (elect. Fuel pump) and noticed immediately that fuel was coming out of the top of the jet even with the piston/needle fully seated. It seemed to me that it was an excessive amount of fuel. After further researching I discovered that there were two different size jets and i of course had the larger ones installed. Installed the smaller size jets corrected the problem.

[kiwi topcat]

had the same problem changed to a hotter spark plug fixed the problem