Running too rich... I think

[Roomsy]

Hi all, I've had my Rapier fastback for a couple of months now (couldn't see a section for these so I stuck this in here, hope no one minds) and everyone who's seen it says it's 'running rich'. Is adjusting this pretty straightforward, even for an idiot like myself? It's running twin stromberg zenith carbs – would a rebuild kit maybe help? Or is there anyone in the Reading area who is a bit of a carb guru that I could take it to? There used to be Phegre engineering, but they're long gone.

The idling is a bit erratic too, sometimes it doesn't want to idle much at all, but if I adjust the idle speed to around 1500 rpm it'll sit there all day, but obviously that's not ideal.

Any help appreciated!

[turbinecol]

First thing to do, check there is oil in the dashpots on top of the carbs (unscrew the black plastic caps), if not put a small amount of engine oil in them, just enough so the damper offers light resitance when you put them back...see if that helps at all

Assuming that doesn't help:
Next up, get the Haynes manual from ebay...then follow very slowly and methodically the method for tuning the two carbs together. It is quite simple but you have to follow a set routine or the adjustments won't help.

You may find you need a new diaphragm or other parts as you follow the process. It is all explained in the text. Go to Speedy spares if you need the kits.

For later cars where applicable, sometimes the MOT stations tune the carbs to pass emissions by leaning mixture, upping the idle, but these Stromberg equipped 1725s generally prefer rich mixture, idle down). You may find the mixture needs a good increase, but make a note of where you started as you'll need to put it back there for MOTs. I know everyone complains this isn't environmentally friendly, but a smooth running car is likely to put out less than a badly running one needing to be revved and restarted all the time

Enjoy and good luck.

[Roomsy]

Thanks for that, I'll have a go!