Carb needle

[nickacb]

Hello, so I have a mini mk1 850 with what I'm pretty sure is the original Hs2 carb. I was having trouble with it so i bought this service kit http://www.minispares.com/product/Class ... o%20search.

The guy who serviced it told me it was 100% fixed and although it's being driving good, I notice some high gas consumption and some smoke so I took it to another mechanic and tells me that the size of the needle is not correct to jet, so he couldn´t close the flow of gas.

Now, how come the jet and the needle are off, if the carb is the original and the kit is the corresponding. Could it be that needle is too old? would you recommend to buy a new original one http://www.minispares.com/product/Class ... o%20search or maybe other size?

thanx

[timmy201]

Your first link isn’t working for me.

SU jets come in .090” and .100”

I believe all HS2 carbs should use a .090” jet. If an .100” jet has been fitted it’ll be very rich
http://www.minispares.com/product/Class ... 9098A.aspx

Changing the jet will mean removing the carb, undoing the choke linkage screw, removing the fuel pipe from the bottom of the fuel bowl. Once you install it you will likely need to recentre the needle/jet so it goes up and down smoothly

[gs.davies]

What needle is in it? The standard 850 needle is an EB. The kit you bought is correct for an HS2. What does he mean, he can’t close off the gas? Default setting is two turns down from level with the bridge and adjust from there until it’s happy on the lift pin. Might be worth renewing needle and spring and checking if the damper is right.

[nickacb]

Yes, mine is a 60 mini with original carb. In order to serviced it I bought the kit

http://www.minispares.com/product/Class ... o%20search

I assume the carb has the original needle, but know my mechanic says is not the right one for the jet provided in the new kit. I think is a bit wierd cause they should match.

The thing is the mechanic said that it is conusming too much gas, but he couldn't restrain the flow for this reason.

Also timmy is recommending to chage the jet not the needle, so I'm a bit confuse.

Dont know if the kit came with the incorrect jet for my needle or the other way around

thanx

[timmy201]

That looks like the right jet for an HS2. As long as it’s an appropriate needle (have you checked the number on it?) it should work fine.

If he’s having problems “stopping the fuel” it could be a number of things:
Wrong jet or installed incorrectly
Wrong needle or installed incorrectly or worn out
Fuel bowl level too high
Fuel pump pressure too high
Fuel bowl valve not closing properly
Damper oil low or incorrect
Spring incorrect

If the mechanic knows his way around SU carbs this should be pretty straightforward for him to diagnose in person

[nickacb]

Ok, all I can say is that as he saw some black somke and hear the sound of the motor he deduced too much gas was passing. He tried to adjust the fuel from a nut located right in the lower part of the carb but inmediatly figure out that there was no more room left t adjust.

Also, I needed to buy the kit cause the first guy who fix the carb said the parts were all worn out, so I guess the original needle is also worn out.

thanx

[LarryLebel]

Maybe you need to find a 3rd mechanic.

[BAD942B]

Ok, all I can say is that as he saw some black somke and hear the sound of the motor he deduced too much gas was passing. He tried to adjust the fuel from a nut located right in the lower part of the carb but inmediatly figure out that there was no more room left t adjust.

Also, I needed to buy the kit cause the first guy who fix the carb said the parts were all worn out, so I guess the original needle is also worn out.

thanx

in actual fact the engine might be too weak with lots of Hydrocarbons & not much CO, check & set the ignition pints gap / dwell to 0.15" or 57 to 63°, then set timing to manufacturers spec which is 3° btdc for distributor numbers 40648A & 40768A or 10°btdc for 40707D & 40767A.
Spark plugs are listed as Champion N5 with the equivalent NGK B6ES but the car will run better on NGK BP6ES which is a projected nose plug.
On an old car like that possibly 4% co & then adjust to smallest HC figure you can get but no lower that 3% co otherwise it will be too weak leading to poor fuel consumption, excessive HC, etc.

[BAD942B]

I would set the valve clearances to start then check the condition of the ignition leads & components as all have an effect on HCs