10 replies to this topic

[Tripyrenees]

Hello,

 

I've just got a 1968 Mini super deluxe 998, and when i start the car, there is HUGE amounts of black smoke that comes out, lots lots lots !!!! First thought carb, so took it off cleaned it all up with new gaskets and bits, put it back on didn't do much. Another problem was that it had no power, it would try and go but was held back !! max 35mph !! So swapped out the carb with another HS2 to see if it changed and yes !! full power again, but still lots and lots of smoke, it can't just be a mixture issue .... i've played around with it and no change at all ...... Any ideas ???

[mini danny]

It could still be a mixture issue. Need to get it rolling road tuned. The black smoke after changing the carb could be a build up in the exhaust and just needs clearing out

Dan

[jpw1275]

Had the car been used often before you bought it or just stored ?

Cheers james

[KernowCooper]

Black smoke is a very rich  mixture which can either be - worn needle and jet, bad needle valve, incorrect float height or incorrect mixture adjustment, Have you carried out a engine tune ? with timing check

[David128]

As above +1

[Tripyrenees]

It had been stored for 3 years without being run, just started it and have kept it running for a bit trying to see if it just needs to be cleared out  but didnt change much. Is it worth taking the head off and giving it a good clean or just focuse on the carb ? Need to book it in for the rolling road but wasnt sure that it was just a carb issue ....

[David128]

How does it sound? How long have you run it for? Does it misfire or pop when you rev it?

[nicklouse]

have you been out in it yet? and given it an Italian tune up?

[carbon]

Also check that the main jet in the carb is free to move up and down - try pulling choke in and out a couple of times, and make sure main jet is returning all of the way back up to touching the underside of the mixture adjustment nut.

[ACDodd]

Tons of black smoke usually means tons of fuel busily bore washing your engine. Check float needle valve and pipe connections and then ensure you are using a gas analyser to understand what your carb is actually doing.

Ac

Edited by ACDodd, 21 October 2015 - 04:42 PM.

[carbon]

Good advice from AC.

 

I have had problems with float needle valves not sealing, in all cases this has been specs of dirt/rust probably coming from the fuel tank getting in between the valve and seat, stopping it from sealing.

 

With an older mini I would suggest putting an in-line fuel filter just before the carb, to catch all of the rubbish.

 

The cheap plastic in-line petrol filters are just fine for this.

Edited by carbon, 21 October 2015 - 05:03 PM.