11 replies to this topic

[JamesleppAFC]

Hi just wanted to know if I left the choke on a bit while driving will it damage my car in any way as it seems to drive better with a bit of choke.

[alex-95]

What year car and what size engine is it? If you need to leave the choke on all the time then you'll need to richen the mixture a tad then you won't need to leave the choke on all the time.

[gazza82]

It will run rich and use more fuel.

Of course it could just mean your carb isn't set up properly ...

[sonikk4]

I'm with Alex here, for the car to run properly needing choke partially on means the carb needs adjusting or there is a timing issue as well.

I would suggest you either adjust your mixture to enrich it and see how that goes or you do a good service of the engine, checking plugs, points and fuel mixture along with your timing.

Out of curiosity has the car been MOT'd recently, the mixture could have been weakened off for it to pass its emissions.

[JamesleppAFC]

It's a 1993 mini sprite 1275 and I've only had it 3 months the next MOT is April.

[jime17]

Could risk bore wash too i dare say.

You could have a leak on the inlet manifold in addition to everything else that's been mentioned. Spray wd40 round the inlet manifold gaskets with engine idling and if the rpm raises a touch momentarily it points to it sucking air where it shouldn't.

[Poppet2]

I'm with Alex here, for the car to run properly needing choke partially on means the carb needs adjusting or there is a timing issue as well.
I would suggest you either adjust your mixture to enrich it and see how that goes or you do a good service of the engine, checking plugs, points and fuel mixture along with your timing.
Out of curiosity has the car been MOT'd recently, the mixture could have been weakened off for it to pass its emissions.

But how can you change the oil mixture?
Also, how can they change it when it is being MOT'd, and not tell you about it?

[Seba5tian]

I'm with Alex here, for the car to run properly needing choke partially on means the carb needs adjusting or there is a timing issue as well.
I would suggest you either adjust your mixture to enrich it and see how that goes or you do a good service of the engine, checking plugs, points and fuel mixture along with your timing.
Out of curiosity has the car been MOT'd recently, the mixture could have been weakened off for it to pass its emissions.

But how can you change the oil mixture?
Also, how can they change it when it is being MOT'd, and not tell you about it?

Fuel/Air mixture, not oil mixture :)!

[sonikk4]

 

I'm with Alex here, for the car to run properly needing choke partially on means the carb needs adjusting or there is a timing issue as well.
I would suggest you either adjust your mixture to enrich it and see how that goes or you do a good service of the engine, checking plugs, points and fuel mixture along with your timing.
Out of curiosity has the car been MOT'd recently, the mixture could have been weakened off for it to pass its emissions.

But how can you change the oil mixture?
Also, how can they change it when it is being MOT'd, and not tell you about it?

 

 

On carb engined minis there is a mixture screw which you can lean the engine off. A decent MOT garage can make an adjustment if its very close and then tell you. I lean mine off before it goes in but the age of my car (75) the emissions are not so relevant unlike newer mini's. 

 

Just remember to tweak it back.

[myredmini]

Once set up properly it should need choke to start and run with no throttle. Once warm it should idle smoothly with no choke and drive and pull well through out with no choke required. Choke is only used for cold starting. Depending on your set up the needle could need re profiling which is what I had done on my mini by my local classic car/carburettor guru.

My 998 mini was set up on a rolling road including timing, fuel mixture etc and a full reprofile on the needle and cost me £84 and best money i have spent. Very reliable too!

My set up is;
998 (std bore) flat top pistons (high compression)
Maniflow freeflow manifold
alloy inlet manifold
hs4 carburettor
aau reprofiled needle
1.625" Maniflow single box exhaust right through to the tip
Cone air filter
Ignition timing is set to 12 degrees BTDC
Accuspark electronic ignition.

Also with this set up the emissions are within mot spec.

[ACDodd]

Yes, driving with the choke out is not the answer. You need your engined tuned properly. The choke will cause general rich running which will promote accelerated bore wear and the need for an engine rebuild.

AC

[Ethel]

Depends how much choke, the first 1/4" inch or so only speeds up the idle rpm. If you are using enough to get fuel enrichment - and that makes it run better, even when warm, then I'd start by checking your ignition. You may also have an air leak in the induction system. since the hif carb's choke is entirely separate to the main jet it could also be compensating for a fault with that.