Technical sticking choke

[Tony Patterson]

I have just bought a 1987 x19 and it runs fine but the automatic choke takes a long time to come off and then very often will come back on again or stick. I gather this has been a problem with x19s and I wondered if manual conversion was the only answer or could I try something else first. If not any ideas where can I get a conversion kit from.

 

[Phil]

Hello,
The auto chokes on these cars can be problematic. If the car hasn't had enough amount of anti-freeze in the water system at some stage, the auto-choke will corrode and bung up. Ideally you want to take it apart and clean it up, un-clog the water ways and make sure the bi-metallic spring can move easily. Unfortunately it is often very difficult to disassemble it without breaking off one of the pipes. I have tried drilling out the screw but that is very difficult to do as all around the hard steel screw is soft alloy. Manual kits are usable but bear in mind that they are not very effective with this carb as it only has a very small amount of movement between off and on.

BTW. When starting the car, it is best to prime the auto-choke by pumping the throttle three or four times before starting it.

 

[jimbro1000]

You can usually clean the choke up without resorting to dismantling it. Pull the rubber pipes off and give them a good clean (flex them and listen to the wonderful crunching noise of all the solids built up inside). Once they are clean you can put them back on the choke housing and hold the other end up. Fix a funnel to one pipe and pour in a strong vinegar solution and wait.

After a few minutes let the pipes drain and then fill them up again.

You should find that all the nasty stuff has dissolved and you can just plumb the pipework back in and refill with coolant.

One of the reasons the choke doesn't work is that it is pretty much the highest point in the cooling system and often air-locks.

When you bleed the cooling system it is generally a good idea to get the rear of the car raised up and carefully slip the upper pipe off the choke housing to let out the remainder of the air.

Finally - if the autochoke doesn't prime on just two presses of the throttle pedal then you still have a problem. In theory it only needs one press. This is purely to release the choke armature from the ratcheted cam in the housing, the cam can then spring back to it's natural position (dependant on coolant temperature). It also dumps a little fuel down the carburettor to help prime the engine - more than three of four presses and you stand a good chance of flooding the engine or worse still draining the float chamber. If the engine has fuel vapour lock problems then you will be left with a real hassle.

Ultimately if you keep the cooling system in good working order the autochoke should work every time.

If the choke has corroded up inside because the previous owner(s) have failed to use a proper corrrosion inhibiting anti-freeze then the choke is the least of your worries. The cylinder head will be in an even worse condition - as will the water pump and the radiator.

 

[Tony Patterson]

Hello,
The auto chokes on these cars can be problematic. If the car hasn't had enough amount of anti-freeze in the water system at some stage, the auto-choke will corrode and bung up. Ideally you want to take it apart and clean it up, un-clog the water ways and make sure the bi-metallic spring can move easily. Unfortunately it is often very difficult to disassemble it without breaking off one of the pipes. I have tried drilling out the screw but that is very difficult to do as all around the hard steel screw is soft alloy. Manual kits are usable but bear in mind that they are not very effective with this carb as it only has a very small amount of movement between off and on.

BTW. When starting the car, it is best to prime the auto-choke by pumping the throttle three or four times before starting it.

Hi Phil, thanks a lot for your prompt reply will give it a go and let you know how I went on.

 

[Tony Patterson]

You can usually clean the choke up without resorting to dismantling it. Pull the rubber pipes off and give them a good clean (flex them and listen to the wonderful crunching noise of all the solids built up inside). Once they are clean you can put them back on the choke housing and hold the other end up. Fix a funnel to one pipe and pour in a strong vinegar solution and wait.

After a few minutes let the pipes drain and then fill them up again.

You should find that all the nasty stuff has dissolved and you can just plumb the pipework back in and refill with coolant.

One of the reasons the choke doesn't work is that it is pretty much the highest point in the cooling system and often air-locks.

When you bleed the cooling system it is generally a good idea to get the rear of the car raised up and carefully slip the upper pipe off the choke housing to let out the remainder of the air.

Finally - if the autochoke doesn't prime on just two presses of the throttle pedal then you still have a problem. In theory it only needs one press. This is purely to release the choke armature from the ratcheted cam in the housing, the cam can then spring back to it's natural position (dependant on coolant temperature). It also dumps a little fuel down the carburettor to help prime the engine - more than three of four presses and you stand a good chance of flooding the engine or worse still draining the float chamber. If the engine has fuel vapour lock problems then you will be left with a real hassle.

Ultimately if you keep the cooling system in good working order the autochoke should work every time.

If the choke has corroded up inside because the previous owner(s) have failed to use a proper corrrosion inhibiting anti-freeze then the choke is the least of your worries. The cylinder head will be in an even worse condition - as will the water pump and the radiator.

Thanks a lot, first time i have used this site and i honestly didnt expect such expert advice in such a short time, once again thanks

 

[jimbro1000]

One last point - the housing for the spring can be rotated to alter the effect of the autochoke. If you look closely you should find a mark on the housing and a few more on the carburettor. The neutral position is in the middle (and has a larger marking), rotate the housing to increase or decrease the effect of the choke.

 

[RDS]

Hello
Which way is to "increase the effect of the choke" ie keep it on for longer? Rotate clockwise?

Thanks
Rds

 

[NEG]

I thought it was anti clockwise, I’d need to check to be certain.