Manual choke

Max_Damage · 05-03-2010 12:55AM #1

Right, I'm a bit off a noob in this field, so go easy!

My Mk3 is the first car that I've ever had with a manual choke. While I know the general idea of them and how they work, I don't fully know the proper proceeder in using one. Do I pull the choke out fully or only 3/4 when starting the car in cold? And after how long do I wait to push it back in again?

unkel · 05-03-2010 01:14AM

Max_Damage wrote: »

Do I pull the choke out fully or only 3/4 when starting the car in cold?

Depends on how cold it is

And it really depends on the car too. You need to get a "feel" for it. Typically here you only need to pull it out slightly in summer and maybe halfway in winter. And you should be able to push back in after 1 or 2 mins.

hi5 · 05-03-2010 01:25AM

The four barrel Carter carb on my Mustang is about half way in winter.
When its started slowly push it in and out to find the best position for future reference,when its warmed up,shove it in.

macplaxton · 05-03-2010 02:14AM

Max_Damage wrote: »

And after how long do I wait to push it back in again?

Push it back in as soon as it can run without. e.g warm. Some cars warm up quicker than others. You'll hear the engine racing when coming to junctions and the like, if it's got too much choke. Feed it in bit by bit as you go along, so it still runs smoothly.

Quickest way to warm a car up is drive straight off. Don't thrash until warm. Don't let it sit to warm up, takes longer and a good way to wear an engine out.

Max_Damage · 05-03-2010 08:09AM

Thanks for the replies lads. Much appreciated.

fuelinjection · 05-03-2010 08:22AM

macplaxton wrote: »

Push it back in as soon as it can run without. e.g warm.

Just what I was going to write. My three motorbikes have chokes on them and the best advice I ever got was to use just enough choke to get them starting and running and turn off the choke bit by bit - just enough to keep them running.

When its cold they all need lots more choke then I would use in the summer and also if the engine is still warm say at lunchtime then the choke is not really much use and they can start with no choke. It is better for the carbs and the engine to use as little as possible. I find it tends to get the spark plugs dirty as well as there is unburnt carbon build ups on the plugs.

antodeco · 05-03-2010 08:32AM

Hmm, Ive always let the mini idle for about 5/10 minutes with the choke out before driving it. Posts above seem to say it's a bad idea!

unkel · 05-03-2010 11:53AM

antodeco wrote: »

Hmm, Ive always let the mini idle for about 5/10 minutes with the choke out before driving it. Posts above seem to say it's a bad idea!

Never mind the choke. Letting it idle before driving off is generally a bad idea. The engine warms up much quicker when you drive the car

--amadeus-- · 05-03-2010 01:26PM

Depends on the engine as well. The Elan (which shares the guts of it's engine with contemporary Fords) just needs a couple of quick pedal pumps and never needs the choke pretty much no matter how cold it is.

Lyre61 · 05-03-2010 03:33PM

THe SM only needs the choke if she has not been started for a week or so, and I have to sit there while the suspension gets itself together.

Like all old cars the Sm has developed "habits" for the want of a better word, and you get tuned into the way it works best after a while.

carchaeologist · 05-03-2010 07:55PM

And if all else fails a squirt of petrol down the carb usually sorts a long idle car out!;):p

ianobrien · 05-03-2010 08:15PM

OP The best thing to do is to ask an old school mechanic to start it and watch VERY carefully and also listen when he starts it. Use the time to learn about the choke. Then the only thing is to learn the pecularities of that car.

Each car is different. My mk2 has a certain way of using the choke while a friends one is different. A lot of it is down to personal preferences. I'd have the choke almost half way back in just after starting and have the choke fully in after a quarter mile. When the brother drives the car, he uses the choke differently.

Also be thankful that it's a manual choke. The auto choke on them can stick on at times resulting in the car drinking like a fish

antodeco · 05-03-2010 08:50PM

carchaeologist wrote: »

And if all else fails a squirt of petrol down the carb usually sorts a long idle car out!;):p

Do expand on that!

carchaeologist · 05-03-2010 08:55PM

antodeco wrote: »

Do expand on that!

If you have a car thats been idle for awhile,my 100A FII is brutal for it,petrol seems to drain from the carb or something,so i just squirt a drop in the top of the carb with the air filter off then turn the key,seems to help the engine draw the fuel up the line better.
Im not sure of the health and safety implications here though!:p

kyote00 · 05-03-2010 09:25PM

only a problem if you set the pirelli calender on fire....:D

carchaeologist wrote: »

Im not sure of the health and safety implications here though!:p

antodeco · 05-03-2010 09:30PM

carchaeologist wrote: »

If you have a car thats been idle for awhile,my 100A FII is brutal for it,petrol seems to drain from the carb or something,so i just squirt a drop in the top of the carb with the air filter off then turn the key,seems to help the engine draw the fuel up the line better.
Im not sure of the health and safety implications here though!:p

Hmm! Straight into the carb, or would you drop it down the dashpot?

maidhcII · 05-03-2010 09:30PM

--amadeus-- wrote: »

Depends on the engine as well. The Elan (which shares the guts of it's engine with contemporary Fords) just needs a couple of quick pedal pumps and never needs the choke pretty much no matter how cold it is.

Most of those would have had the "semi-automatic" weber carb? My capri is the same, you are supposed to give it a few pumps of the pedal to set the choke and it shuts itself off. The reality is the choke doesn't work at all, but at least the car still starts quite well.

carchaeologist · 05-03-2010 09:35PM

antodeco wrote: »

Hmm! Straight into the carb, or would you drop it down the dashpot?

Just a dash down the top of the carb!

3.2 turbo capri · 05-03-2010 09:48PM

firstly as with most old cars , u are supposed to let them idle for a short while before driving away , asfor driving first thing in the morning are wrong needs to warm for better survival rate , of course not all cars are this way but older cars are .and if its a mk3 escort it has hydrulic tappets which cause numerous problems {cvh engine}
As for the choke question , most cars only like half or 3/4 off the way to start but nearly every car is different , one off our capris {injection version} needed a quick double hit off the pedal before it would start , my mk2 {69} cortina needed choke to start but once running u could switch off the choke isntantly .... my 73 rover P6 needs choke for about 5 minutes before it wil idle .... hence each car different ...

fuelinjection · 05-03-2010 11:13PM

As for driving a car straight away when it is cold, modern engines have amazinly tight tolerances on their moving engine parts and use very little oil if any. The alloys used nowadays means that the pistons and barrels do not change shape so much as they heat up, and so you can treat them mean and you won't damage them. In fact on modern motorbike engines they suggest not even having a running in period when you buy them new as they actually get stronger power outputs from a hard use from the crate.

But older engines were built in factories measuring in inches and by craftsmen rather than computer controlled lathes. Also they have more expansion problems between the different metals and the car will last longer if allowed to warm up before using it, and allowing warm oil to get around the engine. In my opinion anyway.

Max_Damage · 05-03-2010 11:24PM

Again, thanks for the advice. So do you reckon with the Mk3, should I let it warm up or just drive straight away? It's very sluggish when it's cold. Very.

carchaeologist · 06-03-2010 01:06AM

Max_Damage wrote: »

Again, thanks for the advice. So do you reckon with the Mk3, should I let it warm up or just drive straight away? It's very sluggish when it's cold. Very.

With any of mine on manual chokes,i try to drive away as soon as i can and push the choke in fully when the car is moving along the road.

3.2 turbo capri · 06-03-2010 01:07AM

ya but this is classic car section , lol , but yes i know what u mean modren engines very different to old cars , as for mk3 , presume escort ? i have series 1 RST ... i would recommend running it for a short while , about 3/4 minutes beforing taking it out as i have had numerous problems over the years with cvh engines and there bloody hyrulic tappets , i have solid ones in mine so as to have less problems lol ..... but again always going to be personal choice , i am the one who has to repair the engines so i have always left them running for a while before driving no matter what car it is , but thats my choice .... i have 6 classic cars and one kinda modern one lol , and also have 6 motorbikes too , 3 80s goldwings , and few others lol ... all would be running for few minutes before i would use anything .....come to that about motorbike even my honda black bird my pride and joy was the same , always run before i toke it out ... that bike i miss , was sold and replaced with my turbo capri .....

Ballykine43 · 06-03-2010 02:53AM

The manual for my 1973 Stag refers not to a choke but a "Cold Start Control", so now we know what it is for.
"Pull out the cold Start Control. Always use the minimum setting for the shortest possible time. As soon as possible after the engine has started push the contrrol completely home"

Most, if not all, Mk 3 Escorts would have had an automatic choke. Many of them gave a lot of trouble and the simple fix was to fit a manual choke.
Starting from cold: If the ignition, plugs, timing are right... full choke should not be a problem. (It may well start with a lot less if its kept in a garage or in warmer weather.) Then back to enough choke to keep the engine running, whether you move off or allow it to warm up. But get the choke off as soon as the car will run without it

The problem comes when you stall a partially heated engine and really have to find the right amount of choke to fire it up again. Too little won't do but with the addition of a couple of pumps of the throttle it might. Too much and you will flood the engine. A hot engine won't start at all on full choke. It was because of these problems that auto chokes were invented.

You will get all sorts of advice about what to do if it doesn't start. Best thing is to find something else to do for five minutes and then come back to it.
Also remember that if you keep the ignition switched on your coil may overheat and cut out till it cools, so don't keep grinding away at the starter for too long.
So just use it. You will soon get used to what your car needs and responds to.

Happy motoring.

Esel · 12-03-2010 12:39AM

Using the choke enrichens the mixture, so I use it as little as possible. The rich mixture is very anti-lubrication, imo. Start, drive away, choke in. If slowing/stopping while still cold, I'll pull it out a bit until I get moving again.

antodeco · 12-03-2010 10:17AM

The issue that I have is that I need to have my choke out all the time. The car stutters (around 3k revs) otherwise. If I have it in and it stutters, I push the choke in and it accelerates fine again.

Anan1 · 12-03-2010 10:37AM

antodeco wrote: »

The issue that I have is that I need to have my choke out all the time. The car stutters (around 3k revs) otherwise. If I have it in and it stutters, I push the choke in and it accelerates fine again.

I'd imagine your carburettor needs setting up so, choke should only be needed from cold. As esel said, it's best to use the choke only when strictly necessary - a rich mixture will strip lubricant from the cylinder walls, resulting ultimately in bore wear.

3.2 turbo capri · 12-03-2010 01:10PM

if u need to have the choke out the whole time , not sure as your message doesnt read well ,u pull it out and shove it back in agian and then it works properally , if thats the case then sounds like u may just have a sticky choke cable , no sure what u mean really , lol ....

kasper · 12-03-2010 02:25PM

antodeco wrote: »

The issue that I have is that I need to have my choke out all the time. The car stutters (around 3k revs) otherwise. If I have it in and it stutters, I push the choke in and it accelerates fine again.

slow running jet probably blocked ,clean the carb and jets should be good if no other underlying problems .its not going to do your engine any good the way it is

macplaxton · 12-03-2010 03:09PM

kasper wrote: »

slow running jet probably blocked ,clean the carb and jets should be good if no other underlying problems .its not going to do your engine any good the way it is

Looking back through the posts antodeco has a Mini. Therefore I guess it has an SU carb. No accelerator pump, so can't be give "a couple of squirts" on the pedal to start it nor does it have a slow running jet. Just one needle, one jet.

The choke cable on a SU carb pulls the jet down to enrich the mixture and may also nudge the throttle flap. Sounds like it needs adjustment.

antodeco · 12-03-2010 04:10PM

Its sometimes fine, sometimes not. I was actually thinking it was dirty fuel thats blocked the filter, so only when the choke is out a higher mixture content allows the car to run...

Manual choke

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