25 replies to this topic

[IainNeon91]

Hi all.

I have recently colour tuned and timed my 998 HS4 w/ stage 1 kit (1 3/4" exhaust). Whilst watching the colour tune, we could get it in the blue but it was still flickering a little yellow, it would do the with the jet nut turned all the way up/lean!

I suggested that it could be because of my float chamber angle...? I will get a better picture up later today.

My question is, is there any way you can make just the float chamber more vertical, as i read that the carb can work at most angles as long as the float chamber is vertical?

Also a good additional question would be, how should a colour look on the colour tune with a stage 1 kit? Am i right in saying it should run a little richer?

Also what have you guys got your advance timing at, with your stage 1 kits? Mines currently at about 10degrees... It ran like S*** at 8degrees...

Sorry about all the questions, any advice will help me a lot!

Thanks,
Iain

[dklawson]

You might also be experiencing a slow leak from the float valve that is allowing excess fuel into the float bowl at idle. You may want to check this by removing the suction chamber and piston from the carb so you can look down onto the carb bridge. Crank the engine over on the starter to make sure the float bowl is filled then look into the carb body. The fuel should be a short distance below the bridge and certainly not coming out of the jet. Others may know and post specific information on where (what height) the fuel should appear in the jet.

For the HS series carbs there are a number of different keying spacers/washers that go between the float bowl and the carb body. I have seen them both plastic/rubber and metal. Burlen must have a list of them somewhere on their web site. You do want the bowl lid to be more or less horizontal once installed. That will also affect the level of fuel in the jet.

[bmcecosse]

The float chamber MUST be vertical If not - as above - use different spacers, or just take a saw/file to the spacer you have. I don't use a colour tune....just lift the piston with the lift pin - or a tiny screwdriver if no pin provided. but in any case - that's just the idle mixture, and what really matters is the running mixture! Check the plug colour after a decent run........

[tiger99]

Funnily enough, I used to use the Colourtune, but found that when I set it up by lifting the piston, it ended up very nearly perfect on the Colourtune anyway, so I did not bother with it again on the Minis. I did use it on other cars with non-SU carburettors.

You bring the lifting pin up against the piston, which you can feel, and when running at idle lift it maybe 3 mm. If the mixture is correct, the rpm will rise only momentarily and then settle back as it was.

[IainNeon91]

Sorry about taking ages for the picture but here it is.

Thanks for the replies, you say spacer? Is that the spacer inbetween the carb and inlet, if so i don't have that because of how my carb sits on the inlet.

Edited by IainNeon91, 04 January 2013 - 04:18 PM.

[rally1380]

Float chamber does look at an angle to me....take the chamber off and have a look at the grommet. If you are lucky it'll have a part number on it so you can see if its the correct 30 degree or (more likely) the 20 degree version.

Edited by rally1380, 04 January 2013 - 04:33 PM.

[carbon]

Also once you have straihtened up the carb bowl you will find that if you refit the original HS4 air filter this should give you better performance than the filter you have fitted.

If you're going to keep the 'performance' filter then I would advise connecting up the water to the manifold. You will get a lot of different opinions on this but I have had throttle jam on a 998 in almost standard tune due to icing. And it does not need to be cold weather for this to happen, just cool damp day can cause it.

[dklawson]

Thanks for the replies, you say spacer? Is that the spacer inbetween the carb and inlet, if so i don't have that because of how my carb sits on the inlet.

No. The spacer Roy and I mentioned is also what Rally1380 is calling a grommet. The float bowl will be held to the carb body with a long bolt. If you remove that bolt you will find a keying washer/spacer between the float bowl and carb body. You need the "right" keying washer to set the bowl angle. Your bowl does look like the washer/spacer needs to be changed. This is a very common occurrence if an intake manifold from a non-Mini A-series engine is used on the Mini.

See step 4 in the Burlen web article linked below. The long bolt and spacer are BOTH labeled as item #16 The washer/spacer is on the zig-zag line between the bolt and bowl.
http://www.sucarb.co...tail.aspx?id=77

[rally1380]

It looks like this.....



I'm pretty sure my one is the wrong one (my carbs are from a mgb), so i'll be buying correct angle ones (need two for twin carbs).

The small rectangular hole is what sets the angle.

Edited by rally1380, 04 January 2013 - 05:13 PM.

[IainNeon91]

Thanks for the replies, you say spacer? Is that the spacer inbetween the carb and inlet, if so i don't have that because of how my carb sits on the inlet.

No. The spacer Roy and I mentioned is also what Rally1380 is calling a grommet. The float bowl will be held to the carb body with a long bolt. If you remove that bolt you will find a keying washer/spacer between the float bowl and carb body. You need the "right" keying washer to set the bowl angle. Your bowl does look like the washer/spacer needs to be changed. This is a very common occurrence if an intake manifold from a non-Mini A-series engine is used on the Mini.

See step 4 in the Burlen web article linked below. The long bolt and spacer are BOTH labeled as item #16 The washer/spacer is on the zig-zag line between the bolt and bowl.
http://www.sucarb.co...tail.aspx?id=77

I can't find that specific part for sale nor a part number anywhere... Don't suppose you'd have better luck

[IainNeon91]

It looks like this.....



I'm pretty sure my one is the wrong one (my carbs are from a mgb), so i'll be buying correct angle ones (need two for twin carbs).

The small rectangular hole is what sets the angle.

thank you for the picture! Im assuming you can get these with bigger rectangular holes then... Just need to find one!

[rally1380]

Not a bigger hole.....the rectangular slot/hole is moved around the curved surface to give different angles. The slot locates onto a rectangular peg on the carb body to give the right angle.

Minispares sell the correct angle ones....search 'float grommet' and it'll come up. Just make sure you order the correct side. I'm buying both so no problem for me.

[rally1380]

Think this is the one you need......double check though.

http://www.minispare...h/classic/float grommet.aspx|Back to search

[dklawson]

That's the one! That will get your float bowl sitting level and may help with the fueling issues.

[IainNeon91]

I have checked and this is the one i need.

Thanks for the help guys!