13 replies to this topic

[krippy31]

1965 mk1

amongst many problem i have had latley ive ended up getting my exhuast fitted propely and sealled new air and oil filters allso new thrush bearing. due to the the exhuast down pipe blowing at the join to the maniold the air filter has dragged up all the rubish and blocked my carb so i took every thing of and cleaned it all after i stupidly started messing with the andvance and retard , mixture screw and tick over.

now i have got it running but it appears to be what i hear is called hunting. i turn the engine over and the revs start climbing as if some ione has pressed the accelerater slightly but if i press the accelerat then let go the revs drop for a second then climb again. i have got the tick over screw right up and ive turn the mixture screw right up and down with no results. i tried just driving to bottom of the road and it had vertually no accelerationit kept trying to die on me yet at idle its reving way to high. HELP PLEASE my mini is my daily runner and after the last 2 weeks i cud cry and i feel abit of a pest because ive asked random questions on here all week but every time sum body allways managers to help me out

[spikyrob]

Check that you're getting a seal between manifold and head, carb and manifold etc etc, mine was idleing very high and turned out to be a leaky gasket

[minitomfoolery]

Did you top your dashpot oil back up when you rebuild the carb?

[krippy31]

yh ive topped the dashpot up and all was nice and free how ever i will check the carb is nice and tight tomoz any one else got any more suggestions thnx

[Kurt]

If your carb is a Hiff 44 - (the one with the large square base) - Try removing your air filter (espaecially if it's a K&N) reducing the tickover screw until the cam lobe on the side of the carb is allowed to come back to it's rest position. Then screw the tickover srew in 1 1/2 turns anfd the cam should just start to move.

This will in effect push you throttle pedal down just a bit. ****Then undo the 3 screws holdig your dashpot on. Remove your dash pot etc so you can see the top of the jet. Screw your mixture screw in or out so you can see the jet move, then make sure it sits flush with the surround (around the jet). You can use your finger to check it's not too high or too low.
Replace the dashpot, only make sure your needle does NOT get bent when you place it back in the jet. Screw it down and then run your engine.**** Use you foot a little or try a little choke if it won't start, but don't flood it.

Set the tickover to 1000rpm. You may at this point need to adjust the mixture (one flat at a time on your screw driver) then give the engine one rev to about 2000rpm max (nothing silly) upon each adjustment, then listen to the engine. You should at some point hear the revs increase or perhaps decrease. Keep going either screwing the mixture screw in or out, until you hear the speed get to it's highest point (you may have just gone past this point and the revs may dip so turn your screw back a step). Go back a touch from where you are now on the mixture setting, to get the carb running at its fastest and with the smoothest even sound (listen to the exhaust is often best), then adjust the tickover to 900rpm or so.
If, when you replace the filter things go wrong, then the filter will either need cleaning (if it's aK&N filter) or chuck it if it's not and buy a new one.

This happened to me this week so my filter is being cleaned!

I hope this helps.

PS Go back to this '****' point above if you get lost on the mixture settings.

[Nightrain]

You checked the throttle cable isn't too tight.

[krippy31]

well ive just had a quick look and i dont think mines the hiff44 carb as its smaller and has the float chamber on the right . i did one once find out wich one it was but ive forgotten. and for my accelreatrer cable it does apper to be loose enough because the accelerater mechanism is right back to as far as it can go and the tick over screw is right out but i did notice the accelerater cable was rubbing on the top of the exhuast manifold which i dont record happening before i took it off. all i can think now is that i need to just keep adjusting the mixture screw until hopefully my revs die down abit i would say it probably running at over 1000 rpm when at idle :S

allso whats the orange light for above my ignition light i feel abit stupid asking but ive never noticed it before

Edited by krippy31, 25 August 2009 - 09:04 AM.

[krippy31]

ive being having a play and now im really fed up this has gone on for two weeks. aarrgghh
so i checked everything was tightly on and it was. the accelerater cable is fine and i turned the mixture screw right up the turn engine over and began slowly turning the mixture screw down and the engine hardly changed tone and i allso notice that when i pull my choke its not doing nothing but the mechanism on the carb moves i have one more week to sort it and then its a new car cause i need one for work

[Nightrain]

If the mechanism is moving I take it you mean the jet holder moves down ? In which case it is richening the mixture as it should, Im guessing you mean the idle speed doesn't increase. In which case you need to adjust the fast idle screw, which is located on the throttle lever, pointing at the choke lever cam. What should happen is when the choke is pulled out, the jet assembly is lowered and the cam comes into contact with the screw on the throttle lever and increases the rev's as well. Sounds like yours needs adjusting, to do this pull the choke out, and then adjust the screw until the required fast idle speed is reached.

[edoddy]

Had this in an old Metro, if you dismantle the carb you will find a little diaphram in it, they sometimes perforate, you can replace it, but i just stuck another carb on. Might be worth borrowing a spare off someone?

[bmcecosse]

Ignore that one ^^^ - there is no diaphragm! You seem to have adjusted everything - without knowing what you are doing. Slacken the accelerator cable slightly - sounds like it is holding the idle speed up no matter what you adjust. then drop the idle as low as it will go - then adjsut the mixture up and down to get smoothest idle. Thn adjsut the ignitiuon timing forwrad and back - to get best idle again - then back to the carb for fine tuning. Simples !!

[krippy31]

Ignore that one ^^^ - You seem to have adjusted everything - without knowing what you are doing.

haha very true and now look wheres its got me

so round 5 it will be tomorrow i really hope i can sort it as some nieghbour down my road seems to have just got himself a mini aswell and its very disheartning when hes bombing about and i cant hah

thanks for every ones help again

[krippy31]

wooo ive got it goin thanks but ive just driven it and she hasnt got much go in her so abit more tweeking. it was the accelerater cable . i think a need a new cable it appears to have frade and broken off so its to short. i think its my andvance and retard that needs tweeking as theres not much life in her but she will pik up and as for the mixture im fairly confident thats spot on as the exhuast is lslightly blue/grey abit

one other thing is i noticed twice thatb i got a puff of black smoke but its not done it since

Edited by krippy31, 26 August 2009 - 09:27 AM.

[ferrox_666]

If you tap the throttle and it revs then drops below idle before returning to normal tickover that indicates.
Try google'ing ''SU piston lifter tuning''..