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shaun
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Ok i will take it apart tomorrow and have a look
Thanks Shaun
Thanks Shaun
Technical Running issues
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Technical Running issues
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shaun
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I have removed the choke housing and the bimetal spring is in good condition and was attached but when i pull the throttle the arm just goes all the way back.On page 78 of the documents you sent me there is a section on the vacuum pull down,would this help with the problem i have
Shaun
Shaun
jimbro1000
Established member
Quick simple test, with the water housing off check the position of the cam. The widest part of the cam should be where the arm inserts into the housing. Make sure the arm isn't slipping down the side of the cam and is actually resting on the cam edge. Now try unhooking the spring (don't let it unwind or spool off sideways) and do the same, the cam should stay where it is but equally you should be able to operate the cam with the tip of a screwdriver as the action should be incredibly light since the spring provides all of the tension.
If you can get the cam in the right position try attaching the spring again and see what happens.
It could be the vacuum pulldown is shot or way out of adjustment (I've never had any success adjusting this) or it could be the tension on the spring is completely wrong or equally that the cam has seized in place - you'll know the answer to that last one if you had no luck moving it at all.
If the spring tension is all wrong see if you can rotate the housing as described for the adjustment (I think it is the spring that actually rotates - its been way too long since I last did one of these).
If you can get the cam in the right position try attaching the spring again and see what happens.
It could be the vacuum pulldown is shot or way out of adjustment (I've never had any success adjusting this) or it could be the tension on the spring is completely wrong or equally that the cam has seized in place - you'll know the answer to that last one if you had no luck moving it at all.
If the spring tension is all wrong see if you can rotate the housing as described for the adjustment (I think it is the spring that actually rotates - its been way too long since I last did one of these).
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shaun
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jimbro1000
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That's the one but I'd forgotten about the tensioning spring that pulls the cam back... said it had been a while....
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shaun
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Hi again,everything looks to be working ok i am going to put it back together and bleed the system again.Is the 11mm headed bolt on the housing a bleeding point ?
Thanks Shaun
Thanks Shaun
jimbro1000
Established member
It isn't designed as a bleed point...
I always found it best to jack the rear of the car up and just ease the upper of the two pipes off to bleed it out.
I always found it best to jack the rear of the car up and just ease the upper of the two pipes off to bleed it out.
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shaun
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Ok i will try that
Thanks
Thanks
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shaun
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I have finished bleeding the coolant system, the bimetal spring and the choke seem to be ok ,but the problem is still there,with the filter off i press the throttle once and i can see the choke plate close.It will start fine but still will not idle any higher than about 700 rpm,the plugs seem to foul up with fuel and the only way to clear them is to keep the revs up to about 2500 rpm when after about 2 minutes they clear and the car idles at about 1000 rpm
I have a K and N filter and have blocked the small pipe off,if i unblock it and rev the engine it is sucking in air,should i keep it blocked off ?
Do i need to clean the jets or change them ?
Many thanks Shaun
I have a K and N filter and have blocked the small pipe off,if i unblock it and rev the engine it is sucking in air,should i keep it blocked off ?
Do i need to clean the jets or change them ?
Many thanks Shaun
jimbro1000
Established member
Sounds like this is going to be a bit tricky....
The choke flap should be closed under idle while the engine is warming up - if it is (but stays open once the engine is hot) then the choke is fundamentally working.
The idle speed is all wrong though and that still comes down to the idle control arm as originally mentioned. If it won't screw in further or doesn't change the idle speed at cold then something is broken/missing/disconnected between the arm and the main throttle plate. Basically while the choke plate (the upper one) is pretty much closed the main throttle plate (at the bottom) should be open slightly to keep the revs a little higher.
The throttle plate opening controls the idle speed - the more it closes the slower the idle speed, if it closes far enough the fuelling switches from the venturi to a sequence of small holes in the side of the main barrel below the throttle plate. The actual fuel flow there is governed by the small grub screw in the side of the throttle (in the base plate) but that should only be altering the fuel mixture at slow (warm) idle.
The only other way to alter the fuel flow/mix is through the float level and the jet size *BUT* since the engine is running fine when warm it can't be this - at least not enough to really upset the idle as you've described. There is no harm in cleaning the jets (one at a time) but I will be very surprised if it solves the problem.
The small pipe on the K&N is meant for a vacuum pipe that you don't have on an X1/9 (at least not a european one) so yes you need to keep it blocked off. It won't make a massive difference but if you want the filter to work properly you need it blocked.
Getting back to the choke can I just get you to go through the system from first principles since I can't see it for myself.
1) With the engine cold, prime the throttle (two presses of the pedal)
- The choke flap should now be closed
2) Without touching the throttle pedal start the engine
- It should start easily
3) From the engine bay work the throttle once
- The choke flap should open and then close again
4) As the engine warms work the throttle periodically
- The choke flap shouldn't move by itself but when you work the throttle it will stay open a little further each time until the engine is warmed and the choke stays completely open.
Work through the 4 steps and update me on the results for each.
The choke flap should be closed under idle while the engine is warming up - if it is (but stays open once the engine is hot) then the choke is fundamentally working.
The idle speed is all wrong though and that still comes down to the idle control arm as originally mentioned. If it won't screw in further or doesn't change the idle speed at cold then something is broken/missing/disconnected between the arm and the main throttle plate. Basically while the choke plate (the upper one) is pretty much closed the main throttle plate (at the bottom) should be open slightly to keep the revs a little higher.
The throttle plate opening controls the idle speed - the more it closes the slower the idle speed, if it closes far enough the fuelling switches from the venturi to a sequence of small holes in the side of the main barrel below the throttle plate. The actual fuel flow there is governed by the small grub screw in the side of the throttle (in the base plate) but that should only be altering the fuel mixture at slow (warm) idle.
The only other way to alter the fuel flow/mix is through the float level and the jet size *BUT* since the engine is running fine when warm it can't be this - at least not enough to really upset the idle as you've described. There is no harm in cleaning the jets (one at a time) but I will be very surprised if it solves the problem.
The small pipe on the K&N is meant for a vacuum pipe that you don't have on an X1/9 (at least not a european one) so yes you need to keep it blocked off. It won't make a massive difference but if you want the filter to work properly you need it blocked.
Getting back to the choke can I just get you to go through the system from first principles since I can't see it for myself.
1) With the engine cold, prime the throttle (two presses of the pedal)
- The choke flap should now be closed
2) Without touching the throttle pedal start the engine
- It should start easily
3) From the engine bay work the throttle once
- The choke flap should open and then close again
4) As the engine warms work the throttle periodically
- The choke flap shouldn't move by itself but when you work the throttle it will stay open a little further each time until the engine is warmed and the choke stays completely open.
Work through the 4 steps and update me on the results for each.
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shaun
Established member
Thanks Jimbro i will try it
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shaun
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I'm guessing you should be adjusting #33 - Fast idle adjustment screw. The one you're pointing at is the "warm idle" adjusting screw, it allows some adjustment of the mixture. Have you checked for leaks between the carb and the manifold?
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shaun
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Yes ppalma i have checked for leaks,but when the choke comes off the car seems to run fine
jimbro1000
Established member
Don't touch the screw you have circled - that will mess with the slow idle mixture and cause more problems.
The screw labelled #33 is the one you want (as already mentioned)
The screw labelled #33 is the one you want (as already mentioned)
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shaun
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I think when i try to start the car and get it running originally i did adjust this screw, could this be the cause of the over fueling when starting.
I will still go through the steps you told me tomorrow
Thanks again
I will still go through the steps you told me tomorrow
Thanks again
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jimbro1000
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The adjustment of screws #9 and #10 is a delicate matter and could cause overfuelling combined with #33 being incorrectly set as the closed throttle plate on the main venturi forces fuelling via the warm idle circuit (controlled by #9). #9 fixes the throttle plate stop, #10 fixes the mixture (my first car used to vibrate #10 out of the carb body - it would start fine but while sat at a junction the idle would get worse and worse unless you raised the revs - fixed with a new rubber grommet on the screw itself).
If you look at the diagram you can see the arm attached to #33 directly controls the throttle plate, in effect it fixes the throttle stop while the engine is cold.
What the diagram doesn't show clearly is how the choke flap is attached and controlled. It is operated by the choke and the throttle together making for a bit of a headache. As long as the choke flap closes when the carb is primed and cold and opens with the throttle then it is not something to worry about.
If you look at the diagram you can see the arm attached to #33 directly controls the throttle plate, in effect it fixes the throttle stop while the engine is cold.
What the diagram doesn't show clearly is how the choke flap is attached and controlled. It is operated by the choke and the throttle together making for a bit of a headache. As long as the choke flap closes when the carb is primed and cold and opens with the throttle then it is not something to worry about.
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shaun
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Hi again
1) With the engine cold, prime the throttle (two presses of the pedal)
- The choke flap should now be closed ............Yes flap closes
2) Without touching the throttle pedal start the engine
- It should start easily.......Yes car starts easily
3) From the engine bay work the throttle once
- The choke flap should open and then close again........Yes flap opens then closes
4) As the engine warms work the throttle periodically
- The choke flap shouldn't move by itself but when you work the throttle it will stay open a little further each time until the engine is warmed and the choke stays completely open.........Yes it does exactly what you said
The choke works as it should do from your steps
1) With the engine cold, prime the throttle (two presses of the pedal)
- The choke flap should now be closed ............Yes flap closes
2) Without touching the throttle pedal start the engine
- It should start easily.......Yes car starts easily
3) From the engine bay work the throttle once
- The choke flap should open and then close again........Yes flap opens then closes
4) As the engine warms work the throttle periodically
- The choke flap shouldn't move by itself but when you work the throttle it will stay open a little further each time until the engine is warmed and the choke stays completely open.........Yes it does exactly what you said
The choke works as it should do from your steps
jimbro1000
Established member
OK - everything is physically working but one or more of the settings is off.
If you've tried turning the fast idle speed adjustment screw to see if it improves the idle speed (1500rpm is where I used to set it) and it made some difference then this is probably the one to change but if it isn't making any difference then you really need to look at other factors and from personal experience it may be a lot easier and significantly less time consuming to get a professional to do the job.
If you've tried turning the fast idle speed adjustment screw to see if it improves the idle speed (1500rpm is where I used to set it) and it made some difference then this is probably the one to change but if it isn't making any difference then you really need to look at other factors and from personal experience it may be a lot easier and significantly less time consuming to get a professional to do the job.
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shaun
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Ok thanks Jimbro
