Hi Guys,

I know there have been heaps of mails on this subject but I need a little assistance.

I have a 1098cc 71 Mini K with an unleaded head, standard exhaust,standard inlet mainfold and reconned 1/4 HS2 SU with standard air cleaner and I use Unleaded premium
normally from Mobile

It runs well most of the time but when I am running in 4th gear at almost full throttle it starts to stutter.

Is this because the mixture is too lean or Rich or is it caused by the engine not getting enough fuel. (is this what they mean by hunting?)

Please Help

Martin

sounds like its running a little lean , you might be better off to upgrade to a hif38 or a hs4 or even a 40mm weber/ dellorto depending on ya budget, back to ya carb, have a look at the jet seat, ( under side of carb) and thered a large nut there loosen it 1/2 to 1 turn (anti clockwise )

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lookin for another clubby

Could be fuel supply problems? Are you running the standard mechanical fuel pump or something better? If the fuel is a little low in the float bowl it can cause it to run lean as the fuel will sit lower in the jet. Could also be your selection of needles not providing the correct fueling at WOT. Does it do the same thing in other gears at full throttle?

I don't think you have to race off and buy a new carb just yet

Thanks Guys,

The car runs fine in all other gears, I can rev it right out without missing a beat, it only happens in 4th at full throttle. I am running the standard mechanical fuel pump but I have read that this should be sufficient. The mini has not always had this problem it seems to have only occurred in the last couple of weeks but I have not changed anything.

I will try adjusting the mixture to see if this makes a difference.

I had HIF38 on my 79 Mini 1000 in the UK and it seemed to do a better job than this one so I have been thinking about an upgrade but I will wait until I can afford to upgrade and probably go for the a stage 1 kit.

Thanks again

Martin

Hey Mini K,

I have almost the same setup as you, 1098 with 1 1/4" SU. Doc Mini was saying that running it on the standard 1 1/4" SU needle makes the engine run alittle lean. You really need twin 1 1/4 SUs in it or better

I dialed mine up one flat richer and seems to be working fine for the short term, I'll have to look into a new manifold and twins at the minimum...

Good luck!
68Delux

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Lillee - 1969 Morris Mini K

What I really said was, "it will run lean if you fit a Ramflo (or similar) foam filter and leave the stock needle in it".

Are you sure the plugs are OK? Sounds like either fuel delivery or perhaps spark plugs are past it, or are to hot a heat range. What are they?

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Woops sorry Doc... Yeah you know what I meant

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Lillee - 1969 Morris Mini K

I know this probably sounds a bit stupid but check your points. I had fun with one of my mates checking his fuel pump and carb etc. after all that we took the dizzy cap off to find the points were dead. It had similar problems to what you are describing.

Thanks everyone for your tips and traps,

Amazingly, it turned out to be really easy to fix I adjusted the mixture anti-clockwize 3/4 of a turn. I took the car for a run out to newport and back on sunday (about 30 kms) and the problem has dissappeared, the mini ran like a rocket.... I think the mixture has been out since I changed to an unleaded head (about 2 months agao) but I never really noticed it until recently when I started driving the car harder.

Many thanks

Martin