BX16 Auto choke

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Aerodynamica
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BX16 Auto choke

Post by Aerodynamica »

I know! I know! it's known to be a common iffy issue but I am not sure that the auto choke on the BX is working as it should.

I sometimes find that after a period of rest (say less than 2 hours) when started again the choke seems to be on - should it be? I thought it was only needed for starting from dead cold first thing.

Any advice?
Graeme M

CX 2400 Pallas LPG
2CV6 dolly (SORNed)
Mk1 Xantia 1.9TD SX

'c'est hydropneumatique'

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DLM
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Post by DLM »

When I owned a couple of BX16s there was an addendum page in the handbook advising 2 quite different procedures to use when starting from cold/hot with an autochoke BX. Can check - may still have a copy of this sheet.

From what I remember, one involved "no pedal", while the other advised fully depressing accelerator pedal and then releasing once the engine started (think this was the hot start). Does this perhaps trigger an override for the autochoke mechanism? Or perhaps I should check the Haynes Carb manual mouldering on my bookshelf...
Relying on two wheels and musclepower since the last BX (or any car) had to go.

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mnde
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Post by mnde »

Hi Graeme,

Do you mean you are having difficulty re-starting after short journeys?

Or do you mean restarting 2 hours after you've completed a long journey?

In the GSA, I'd expect to have to pull the choke out a little after 2 hours at rest.

Dave, you are right about the hot start. Fully depressing the accelerator operates a linkage that opens the choke butterfly a certain amount. I've only verified this with my spare carburettor off the car, so I'm not sure what happens under hot conditions. And I don't know how long it would take, after switching off a hot engine, for the waxstat to start gradually closing the choke butterfly again.

Mark.

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Tim Leech
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Post by Tim Leech »

Ive owned over 10 carb fed bxs, one was relativly new at the time but still a pain to start when warm!, my current TRS has the original "starting guide" sticker attached to inside of the windscreen, which states "do not touch the throttle" AT ALL when starting from cold, but once warm "do not hesitate to depress the throttle fully and keep the starter working for upto 10 seconds"! If I do that and it normally coughs into life first time but pops and farts for a second or so, if I dont touch the throttle it wont go.

One intergallactic mileage 16TGS I had was converted to manual choke and was a bit better, the 19TRS auto I ran late last year was a swine any other time except the first start of the day yet the 19GT which is basically the same car fires up immediatly when warm without touching the gas pedal yet needs some cranking when cold :roll:

French cars ey!
Last edited by Tim Leech on Mon Nov 10, 2008 8:07 pm, edited 1 time in total.
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demag
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Post by demag »

I took my Bx for some new driveshaft gaiters the other day and it hadn't been started for about 3 weeks. I didn't think it was going to start from cold. I tried no throttle, full throttle, pumping throttle and just as I was about to give up it burst into life from no signs of firing at all. I do know, however that the choke is all over the place. I think its miles too rich on start up and kangaroos up the road for two or three minutes, but once its warm its ok. The few times I have left it for an hour or so its started great.
Dave.

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1990 Bx TGS automatic.

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Post by ellevie »

I can also confirm my handbook recommends pressing the pedal to the floor for hot starting.

It's fairly easy to check the basic operation of the Solex autochoke as follows,
Remove the hood or air duct from the top of the carburettor.

With the engine completely cold the choke flap should be fully closed.
Image

Within about one second of starting the engine, the flap should open by as much as 6 mm to the so called "pull-down" position.
Image

As the engine warms up the flap should gradually move to the fully upright or fully open position. This could take about 15 minutes.
Image

For some background on the "pull-down" see http://www.bxclub.co.uk/forum/viewtopic.php?t=1478

This pull-down fault could also be the cause of Dave-demag's problem especially if the engine tends to stall just after starting.


David
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Aerodynamica
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Post by Aerodynamica »

Thanks for the great responses guys! I'm gonna just chill actually because I think it is actually functioning as it should.
"do not hesitate to depress the throttle fully and keep the starter working for upto 10 seconds"! If I do that and it normally coughs into life first time but pops and farts for a second or so, if I dont touch the throttle it wont go.
- this is exactly what happens on mine.

Good comprehensive photos ellevie - thanks.
Graeme M

CX 2400 Pallas LPG
2CV6 dolly (SORNed)
Mk1 Xantia 1.9TD SX

'c'est hydropneumatique'