Carb jets

[Adder57]

Has anyone got the answer to this question: Are the jets on hs6 carbs supposed to be the same. Two cylinders seem to be running very rich compared to the other two which are very weak. On inspection the right hand carb (nearest rad) has a slightly bigger hole to the other carb, and one is red on bottom of the jet and the other is black. The car will not run right unless one is a lot higher than the other. Is there someone who can solve this. Regards adder

[marshman]

Short answer is yes. The only difference is one is for the left hand carb and on is for the right hand carb.

The fact that the jet bases are different colours (one red and one black) shows the jets are different, i.e not a pair, (not just LH and RH). But it doesn't indicate in which way.

There are only two jet sizes - 0.090" and 0.100" and the red/black colour does not indicate the jet size.

If you look closely you may be lucky and see that there are some coloured rings /bands on the pipe between the jet head and the float bowl. Knowing the colour of these 1 or 2 bands AND the colour of the jet head will identify the jet.

From your description it seems you may have one jet at 0.100" and the other at 0.090". The 0.100" one I guess will be the one that is running a lot richer.

Sprint Jets (assuming it is a Sprint as you are talking HS6's) up to 1976 should be AUD9105 and AUD9106, both with red jet heads. one should have a yellow band the other orange, and both should be 0.100" jets.

[Adder57]

Thank marshman,it is for a sprint can't see any colours on jets. But the left carb is definitely .100 the other one is a throw fit on .100 I used a .100 drill just to see the difference. Do I need to replace one jet or is it best to get a matched pair. Thanks.

[Adder57]

Ah, spotted the coloured bands the one that is running rich is orange the weak one is green. Don't know if that helps.

[marshman]

OK I am assuming the orange band is on the one with the Red jet head which should be on the front carb (I think!) which is correct. I also assume the one with the green band has the black head which makes it a AUD9141 which is a 0.090" jet, hence why it is weak, that is wrong! If that is the case then you only need replace that jet with an AUD9105 (red jet head with yellow band) on the rear carb.

The above is guess work given the info provided and the fact they they don't list a red jet head with a green band!

[Adder57]

You are correct, red jet orange band very rich right hand carb, black jet green band very weak left hand carb. The needle size is .098" . The very rich jet is only. 060" from the top of the bridge and needs to go up more, I'm thinking this could be worn so maybe needs replacing. What are your thoughts. Oh the weak jet is .115" from bridge. Regards adder

[Carledo]

I'd be inclined to start fresh with a new pair of jets and needles. Then you have known correct parts everywhere and have also eliminated the possibility of wear. All the right parts are available new from Burlen and other suppliers and not horribly expensive.

Steve

[Adder57]

That was my thinking, I'm only trying to correct someone else's bodge . If I get both then at least it's a good starting point when I try to set them up. It's always good to have a couple of views. This all came to light after I took the car to be tuned. Thanks for the help regards adder.

[marshman]

Yes, agree with Steve. Start afresh get new jets and needles. Also check the carbs over as they have obviously been bodged in the past.

[Adder57]

I've sent for some new parts,jets needles etc. I'll fit them to the carbs then take it from there. Thanks for all your help I'll let you know how I get on. Regards adder.

[Adder57]

Good morning, just to update you on my jet problem. Fitted both new jets and needles, checked everything reset the throttle and linkage. Had a go at setting the carbs up from the thread on the forum, it seems to alright, took it for a run pulls OK and now idles nice. The only thing I can fault is when is idling for a few minutes the plugs start sooting up, I've read a few people have had this problem. Thought it might be tight valve clearances so checked them, inlet are OK exhaust are all around .015" don't know if this is an issue my other Thought way maybe valve stem seals but I couldn't really see them because of the springs. It doesn't burn oil when driving. What about using hotter plugs at the moment I'm using NGK bp6efs any ideas on this. Adder.

[Magenta Auto Sprint]

If the plugs are sooting up I would suggest that you are running too rich.

[Adder57]

After a run the plugs are fine, they only soot up when the car is idling, would running hotter plugs sort this. I did suspect valve stem seals.

[xvivalve]

After a run the plugs are fine, they only soot up when the car is idling, would running hotter plugs sort this. I did suspect valve stem seals.

Symptomatic to an extent of the ‘quality’ of fuel they foist upon us these days!