9 replies to this topic

[oltonlad]

we went out in the mini yesterday, (it was rolling roaded last week) everything was fine for a while but after about an hour of driving about (mixed driving, open roads and traffic) the tickover didn't seem right, and when i went to start the car it didn't fire up straight away and there was a smell of fuel, so i took the car home and left it.
i went to the car this evening and removed the plugs (they were all really black) it started ok though, but then it started to misfire, i diagnosed it to number 3 cylinder not firing so i changed the plug on number 3 and it seemed ok for a bit, but when i leave it to idle it seems as if it is overfuelling and choking itself and starts to splutter until i rev it and then i clears and seems fine until i leave it to idle again for a bit.

why would it do this all of a sudden..........any ideas?

[Bungle]

what did the guy that did the rolling road tune up say ?

[oltonlad]

i haven't spoken to him yet as i only had a look at the car when i got in from work at 6.30, i'll give them a call tomorrow and see what they say, just seems a bit odd thats all.

[jaydee]

Thats not good, do you still have the old needles and did they changed the advance curve together with the needles?
Try to rule out the odd lucas electrics by checkin/replacing points-condenser at first, and check the coil connections too..
Struggle to start when engine warm (and the fuel smell aswell) suggests that maybe either too rich at tickover or have a problem at the needle valves in the float chambers, flooding the engine.
I guess if you remove the dashpots you'll find a fair ammount of petrol in the choke..
Another test i'd suggest, drive the car a bit, with engine warm, then stop the car and give a look at how engine settles at idle, if its a bit higher than normal, then drops down a bit after few seconds, its too rich.

[the.stroker]

Where did you take it??
Is this the first time you have used it since the rolling road?? , if so I would take it back to them!

[oltonlad]

thanks guys, the car was tuned at hi-tech motorsport, i have just called them and they said that mick is away in spa until monday but he will call me and arrange to take it back so that he can have a look at it, i started the car first thing this morning and it started with no choke at all, it was idling ok though but i didn't have time to let it run as i had to go to work, i will try it later and see how it goes.
the points & condenser were both new when i put the engine in and the carbs were fully rebuilt last year, i had no problems with it until i took it to the rolling road, it was running fine until the tuesday and then it started playing up,the plugs were a light brownish colour before but now they are black.
i definetely seems rich to me, the needles were not changed when the car was set up but i do know that he richened the mixture up, i will take it for a run and check the colour of the plugs again.

[jaydee]

Lean mixture off 1 1/2 flat.
I wouldnt blame it on the RR operator as he just did one run and car was good at the time, also many things can happen like clogged air filters or faulty condensers. Also twin carbs require more attempts to set up correctly because the balance is all a bluff.

[Bungle]

i wouldn't touch it

the rolling road garage seem willing to help so let them have another go

[oltonlad]

i think that i will just take it for a run and see how it goes, i may change the thermostat for a 74 degree one as it was running at 3/4 up the gauge, i've only got to use the car for ragley hall on sunday and its not far away really so it should be ok, i'm not going to mess with the mixture as bungle says, i'll let hi-tech sort it out.

[carbon]

Have you got a fuel filter fitted just before the carb? A bit of dirt in petrol can stop the float needle sealing properly which can lead to running rich.