7 replies to this topic

[Fullarmor]

Hi guys,

 

just wondering, what could be problems making black smoke while choking

 

when I first pop up the engine with choke pulling out in the morning, black smoke coming out

 

choke off, no smoke but at high rev some black smoke coming out also.

 

Do I need to replace head gasket and all the exhaust gaskets? and what could be a problem?

 

seems very old the exhaust gaskets.

 

Cheers

[Spider]

Don't use quite so much choke.

 

The choke richens the mixture a lot and black smoke is usually from a very rich mixture.

[carbon]

+1 for Moke Spider's suggestion about checking for over-rich mixture

 

Is carb/engine standard or modified?

[sledgehammer]

+1 on above ...

 

also maybe look at air filter

 

it is overlooked a lot  but can make a big difference to engine performance , MPG , engine wear & exhaust smoke

 

remember black smoke usually means petrol wasted = £££ (other currency's are available)

 

also make sure choke mechanism is free in all positions - choke returns correctly 

 

best of luck

Edited by sledgehammer, 19 September 2015 - 10:48 AM.

[Fullarmor]

Carb is i believe standard hs4 su single carb. How to adjust it then? Just adjust the bottom mixture nut? Air filter is looks pretty good.
Ill check the choke returning condition. Thank you.

 

ive attached two pictures.

 

first picture, Do I have connect air hose line for the big tube on air cleaner?

https://scontent-sjc...f1c&oe=565DC149

 

second picture, Do I need to adjust the nut at the bottom to decrease fuel going? will it make stopping black smoke while choking? I don't use choke unless staring up the engine in the morning but just want to fix the black smoking problem.

https://scontent-sjc...c5f&oe=565EFDC0

Edited by Fullarmor, 19 September 2015 - 10:10 PM.

[peter-b]

If it runs fine without choke you don't need to adjust anything. If you're getting black smoke push choke in until it nearly stops smoking, its normal to get a bit with choke on. Unless its abnormally cold you should be able to pull choke out, start car, push choke to about half way in, run for 30 secs -1 min, then push choke right in.
One thing you might want to check is, and I think the HS4 had them, is the clip that holds the choke cable outer to the bracket on carby. Without this clip the choke can work a bit odd, feels loose and inaccurate.

13H3472 Is the part number.

Also, while i think of it, if its stalling you might want to check the chocke fast idle, that's the adjustment that allows engine to run faster with choke on.
I'm not being smart but if you aren't real familiar with the SU carby, i suggest leaving it to someone who is, they can be a wee bit finicky when it comes to adjustments.

[Spider]

There's really not much adjusting as far as the mixture goes, with the choke. Adjusting the Mixture nut won't change anything as far as the Choke goes. The only mixture 'adjustment' for the Choke is how far you pull the choke handle out. There is a Fast Idle Speed adjustment.

 

The Choke on a Carb was never intended to be a carefully meter device in any case.

 

For my cars, I find I usually need full Choke to start them, but almost immediately, I can push the Choke in about half way, then after about 1 mile, I can push it all the way in, a bit longer for colder times of the year.

 

As Pete touched on ^ you may need to adjust the fast idle if you find you need to run with full choke for extended periods and if you don't you are finding it stalls.

Edited by Moke Spider, 20 September 2015 - 12:50 AM.

[peter-b]

I never use the choke on mine, not at all.............its an SPI.