14 replies to this topic

[quainton121]

I spent most of Saturday painstakingly cleaning the carburettor on my mini. After refitting the car wouldn't turn over properly it would only idle on the choke and even then it was spitting and misfiring and any throttle it would cut out, none of the settings were adjusted in any way (of that I know)

here is a list of the things removed for cleaning:

dashpot, piston w/needle attached throughout, throttle assembly and complete jet assembly. The main body was also cleaned all moving parts were oiled

Any help would be much appreciated.


---PLEASE NOTE ISSUE RESOLVED---

Edited by quainton121, 20 July 2009 - 02:08 PM.

[m1tch]

I spent most of Saturday painstakingly cleaning the carburettor on my mini. After refitting the car wouldn't turn over properly it would only idle on the choke and even then it was spitting and misfiring and any throttle it would cut out, none of the settings were adjusted in any way (of that I know)

here is a list of the things removed for cleaning:

dashpot, piston w/needle attached throughout, throttle assembly and complete jet assembly. The main body was also cleaned all moving parts were oiled

Any help would be much appreciated.

WHat mods has the car got? might be the wrong needle if you have mods and an ADE needle, have you tried to fine tune the mixture using the screw on the bottom of the carb?

[newdawn1st]

this may help, clicky

[lrostoke]

did you put some oil in the dashpot when you rebuilt it

[quainton121]

did you put some oil in the dashpot when you rebuilt it

yes the dashpot was refilled with thin oil

[m1tch]

What needle is the car running?

[quainton121]

What needle is the car running?

I really don't know, surely it wouldn't be the needle as the carb was running before it was disassembled

[m1tch]

What needle is the car running?

I really don't know, surely it wouldn't be the needle as the carb was running before it was disassembled

My car was running fine before I cleaned the carbs up, it blasted away 26 years of rubbish from the jet that was making it run rich, the car wouldn't even start with my stage 1 kit on it - I drove it back from my mates when it was gummed up and it worked fine until it was cleaned.

Are you running any performance parts?

[zebidee]

You say the settings have not been changed; the mix and idle speed would be set for when the carb was in a poor condition (or worse than it is now). Now that its clean it will surely be running differently. I would try and set the carb up fresh if I was you.

[quainton121]

What needle is the car running?

I really don't know, surely it wouldn't be the needle as the carb was running before it was disassembled

My car was running fine before I cleaned the carbs up, it blasted away 26 years of rubbish from the jet that was making it run rich, the car wouldn't even start with my stage 1 kit on it - I drove it back from my mates when it was gummed up and it worked fine until it was cleaned.

Are you running any performance parts?

Yer it has a 2.5'' twin DTM centre fletcher exhaust and pipecross air filter everything else is standard

[m1tch]

You would need an AAA,AAU or AAV needle, here is my topic:

http://www.theminifo...;hl=bent needle

sound exactly like whats up with yours

[zebidee]

Had you made these mods before the carb was cleaned or during it was off though?? I presumed these were before since you hadn't mentioned them, in which case surely the needle would have already been changed, or would have been running just as poorly before cleaning.

[dklawson]

No one has come out and asked this directly yet, but what exactly did you "do" when you put the cleaned carb parts back together?

The carburetor is an assembly that doesn't just go back together like bolting on a bumper, there are several adjustments that must be made. You have to set "initial" adjustments to get the car started, then adjust the mixture and fast idle settings when the engine is at operating temperature. If you didn't do this, the car is not necessarily going to run... and you're lucky you got the engine to start at all.

If you did NOT make the basic setting adjustments for starting (followed by running adjustment) read the section of your manual that discusses carb adjustments following a rebuild. If you don't have a manual, Google for "tuning SU carburetors" and read up on the process. Also, the link provided by Newdawn1st should take you to a wealth of SU information well worth browsing through.

[quainton121]

Had you made these mods before the carb was cleaned or during it was off though?? I presumed these were before since you hadn't mentioned them, in which case surely the needle would have already been changed, or would have been running just as poorly before cleaning.

the mods were on the car previous to the cleaning i was told the carb had been tuned when i brought the car but from the looks of this it was some time ago. the car before cleaning was down on power felt realy rough on exceleration and was hard to start

[dklawson]

It's too late to offer this comment and have any effect, but for future reference....

SU carbs are often blamed for problems that lie elsewhere. Always start a tune up with setting the valves (on a cold engine) then go completely through the ignition settings (replace components, set points, set timing). Save all fuel adjustments (and in this case cleaning) for last.

The following quote is often attributed to Lawrie Alexander of British Sportscar Center
"90% of the problems with SUs are due to Lucas electrics"