Running rich...
Discussion
Sometimes I wish I hadn't started....
Car starts like a dream but runs VERY RICH....BLACK electrodes on the plugs.
1330cc MG Metro base, newly rebuilt with standard MG Metro carb & manifold. Carb has a Minispares needle (so it could be that I suppose). Compression 200 -220lb/sq in. on all 4 cylinders. Good sparks. There are a number of breather pipes which are not used and blocked off. Two on the manifold which went to the servo and to an anti run on device (I think). One on the carb which went to ???. Screwing the mixture screw a long way out seems to help but not that much. Any bright ideas?
Whilst trying to sort this (which only came bout 'cos I needed to move the car to get something into the garage in the dark) I discovered an oil leak (pressure release valve) and a water leak (stat or pump not sure), got another scrape on my head from the bonnet catch and a bloody finger. Oh and nearly got knocked off the bike again today..
Tony H
Car starts like a dream but runs VERY RICH....BLACK electrodes on the plugs.
1330cc MG Metro base, newly rebuilt with standard MG Metro carb & manifold. Carb has a Minispares needle (so it could be that I suppose). Compression 200 -220lb/sq in. on all 4 cylinders. Good sparks. There are a number of breather pipes which are not used and blocked off. Two on the manifold which went to the servo and to an anti run on device (I think). One on the carb which went to ???. Screwing the mixture screw a long way out seems to help but not that much. Any bright ideas?
Whilst trying to sort this (which only came bout 'cos I needed to move the car to get something into the garage in the dark) I discovered an oil leak (pressure release valve) and a water leak (stat or pump not sure), got another scrape on my head from the bonnet catch and a bloody finger. Oh and nearly got knocked off the bike again today..
Tony H
From what little I can remember of SUs, the mixture is set by the spring and needle profile, and the adjuster you mentioned is just used to set the jet height. And there's basically one right position for that and then you leave it alone. Do you have any reason to think the needle and spring are right for that engine tune? Is is possible that the float has failed or you have too much fuel pressure or some other problem leading to too high a level in the float chamber?
Standard needle profile for MG Metro is BDL (Marked on base of needle). Check this for starters. If the rest of the motor is stock MG Metro, the fueling should be spot on or even a little lean (due to increased capacity). Make sure the needle seat is clean and not gummed up as this tends to promote overfuelling.
Going to put the original jet back in (when I find it), the one currently fitted was supplied by Minispares to match the engine spec - 1330/Evolution cam/LCB/HIF44/standard head.
To the catalogue of niggly probs, i should add: noise from the clutch that sounds like I have left the socket set in there, struggle to select gears, (clutch has seized acouple of times whilst the car has been left in garage), stiffer steering than i remember, pleased the garage doors still work!
To the catalogue of niggly probs, i should add: noise from the clutch that sounds like I have left the socket set in there, struggle to select gears, (clutch has seized acouple of times whilst the car has been left in garage), stiffer steering than i remember, pleased the garage doors still work!
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