16 replies to this topic

[ben360]

Hi,
Standard 1986 Mini Chelsea set up 988cc.

Today noticed my choke will not fully release, the cable is slack when the choke is in fully. this has led to my engine constantly flooding whenever i slow down to below 1500 revs... i try to force the choke back by hand but it will not go any further. My knowledge of cars etc is pretty limited any easy fix for this? or am i gonna have to shell out for a garage fix,... again =(

choke itself works fine for starts etc although havent needed it too much this summer, also no idea how long this lil problem has been sucking my petrol out either so want to get this fixed ASAP.

Also need to replace an air pipe leading from carb to engine? any idea where to get one, this i can obviously fit myself..

Cheers

Ben

[Ethel]

Noot sure which pipe you mean, there's the really think one for the vacuum advance on the distributor or the 1/2 inch bore engine breather hose, both should be available from a local motor factors, though few cars have distributors now, so you might be better off with Minispares or Ebay for that.

Try pulling the choke cable from the carb end. If there's slack cable where it attaches to the lever on the carb it might be a bent jet - it can happen if the engine rocks enough to let it hit the bulkhead.

[ben360]

Noot sure which pipe you mean, there's the really think one for the vacuum advance on the distributor or the 1/2 inch bore engine breather hose, both should be available from a local motor factors, though few cars have distributors now, so you might be better off with Minispares or Ebay for that.

Try pulling the choke cable from the carb end. If there's slack cable where it attaches to the lever on the carb it might be a bent jet - it can happen if the engine rocks enough to let it hit the bulkhead.

Pretty sure its the breather hose as its around 1/2 inch.. runs from the left side of the engine to the left of the carb... (if facing the engine from outside)

bent jet?? sorry.. amateur.
can i check this without removing carb? dont really want to have to start taking all that off. the choke moves fine to a point but won't extend right out as if its catching on something. But as i have no idea how the choke system works i don't even know where to start looking for what its caught on?!!

[Carlos W]

Have you got a haynes manual?

[ben360]

i did have one but i cannot for the life of me find it... I think it has probably been left and forgotten

[Ethel]

http://drcwww.uvt.nl...bogaard/manual/

You ought to be able to diagnose the cause without stripping anything, if it is the carb it's easier to remove than struggle with it in situ.



The jet is the lowest bit in the piccy, yours might be red plastic instead.

[ben360]

i managed to sort the choke out this morning, thanks to a bit of fiddling around,, the cable was caught somewhere so i just re fitted it and that seemed to work.
although it has improved still having trouble keeping it ticking over or it on occasion cuts out when stopping at lights etc...

do i need to adjust the idle screws on the carb because now i have sorted the choke it seems to be under fuelled?... and if so guide of how to?
Middle of summer i should definitely not be need to have my choke out for long if at all, but still when i stop at lights if i dont pull it the engine can't quite hold on.

spoke to a friend today too who said maybe the needle has been cracked and that may be whats flooding it? how can i check this

[Ethel]

I think your friend will have meant the float. If it is flooding pulling the choke more than a 1/4-1/2" would make it worse.

Your best bet might be to do some reading so you can understand and tune your Mini's ignition and carb. It's not that daunting really

7GRAcqDySog

He has plenty of other good vids that are as relevant for Minis as MG's http://www.youtube.c...u/9/4nvGLgO6pj0

[ben360]

Thanks for all the replies, just spent half hour adjusting the throttle etc and i think i have got it ... just needed to adjust the throttle screw slightly.

Just want to check though because i was a little worried, i managed to slightly adjust the mixture screw on the jet below the carb slightly as i was advised earlier to get the mixture right but i could notice a huge difference when adjusting this... i know turning it one way really made the engine choke up but screw the other direction it tended to sound exactly the same however much i adjusted it. The only difference was the more i adjusted it the less responsive the throttle adjustment seemed to get. Could that be a sign of a problem or is that usual?? just going on what i have read up about this the mixture adjust nut on the bottom should make a difference to the 'smoothness' right??

[Notay]

Thanks for all the replies, just spent half hour adjusting the throttle etc and i think i have got it ... just needed to adjust the throttle screw slightly.

Just want to check though because i was a little worried, i managed to slightly adjust the mixture screw on the jet below the carb slightly as i was advised earlier to get the mixture right but i could notice a huge difference when adjusting this... i know turning it one way really made the engine choke up but screw the other direction it tended to sound exactly the same however much i adjusted it. The only difference was the more i adjusted it the less responsive the throttle adjustment seemed to get. Could that be a sign of a problem or is that usual?? just going on what i have read up about this the mixture adjust nut on the bottom should make a difference to the 'smoothness' right??

when adjusting the mixture screw at the bottom (if you need to) try to rev the engine because effectively you are just setting the mixture up for not just idle but for the whole rev range too - your jet controls how much fuel to place into combustion for a certain engine speed/load and if the mixture screw is not set right you may either put too much fuel in or not enough in and hence your car will be difficult to operate at high loads such as going up hills (hence the less responsive feel you are experiencing). You can also never really get it right without taking car to a rolling road who can simulate the loads the engine would feel and adjust the mixture and throttle accordingly.

Also if you are not already doing so - make sure the car is warm at opearating temperature and then any adjustment can be carried out.

Finally if you get yourself a multimeter with a tacho on it you can 'see' the revs drop/increase as you adjust the mixture screw. I think you want around 1000 revs at idle but check Haynes manual first. Hope that helps.

[ben360]

I did have it warm.. that i figured. but i didnt rev at all just adjusted at idle.

When i took it out after it did feel a little less pokey as i went up a hill.

I will have to wait for an extra pair of hands but i think i will be able to get it sorted now!!

Thanks for the help and links, all were a big big help! I think i know my way around my carb a million times better now!

[Ethel]

As in the 2nd video, and as Notay says, you want to be sure everything else is right and the engine has warmed up before touching the mixture nut. since you've found it just confirm the jet moves freely in it when you move the choke lever.

PS you should be revving the engine as well when going vrum vrummmm

[ben360]

As in the 2nd video, and as Notay says, you want to be sure everything else is right and the engine has warmed up before touching the mixture nut. since you've found it just confirm the jet moves freely in it when you move the choke lever.

PS you should be revving the engine as well when going vrum vrummmm

Yeah I did check it was all moving freely and that it had warmed up.

Only thing i hadn't done was get it revving while i adjusted. Might have to get mother to give the throttle a poke while i adjust!!

Thanks for the help much appreciated

Ben

[ben360]

Quick question again sorry. When i am revving and adjusting mixture what is my ideal setup?

Do i want the highest revs possible with the mixture? Or do i just want to hear it running smoothly?

[Ethel]

Just lift the throttle at the carb end.


Screw the nut in to make it leaner, that's anti clockwise as look from above. Half a turn at a time is more than enough. A lifting pin is really handy on a Mini carb, because of the inlet elbow. You can bend a bit of stiff wire to make a "piston lifting hook" if there isn't one - in place of the Twist screwdriver twist.



The aim is to adjust the mixture to get the highest idle speed possible, that indicates the fuel/air mixture is in the right proportions to burn most efficiently.

so the sequence is;

set the idle (800-900rpm)
adjust the mixture
readjust the idle if needed

When it's right lifting the piston will cause the revs to briefly rise ('because there's less restriction) before settling back to the same or slightly less rpm as the mixture gets too weak. If the revs increase and stay higher it's too rich - if it really struggles or stalls it's too lean.

Remember the vrum, vrums: adjust - rev - check... that's the fun bit