SU carbs were used on the early Triumphs, while ZS carbs were used on the later ones. While they are interconnected, they are also independent, and need to be measured and adjusted independently. The trick to tuning Skinners Union (SU) or Zenith Stromberg (ZS) carbs is to understand that there are two things you need to get right: the air flow, and the fuel mixture. Ironically it is a 73 so exempt from the emissions test.Īdjusting Your Carburetors 1. I will get round to checking the CO again but am quite happy with it at the moment so I'm not going to fix something that isn't broken as they say. Having said that the car does run fine and shows no sign of running weak, Plugs, tail pipe or performance, running temp and so on. I spoke to the supplier who assured me it would come up with use and is quite common!!! I have a similar issue and toyed with lowering the jets, I fitted a set of recon carbs from a well know carb specialist (I bought them from someone who didn't end up using them) I couldn't get the CO above 1% at idle. PS the Estate passed its MOT yesterday, and I retaxed it today, Oh how I love tax exempt cars Hi Neil, I suppose the jets need knocking down a little more, I was thinking about 1mm, does that sound about right? I have rebuilt the Strombergs on the Estate after experiencing flooding problems, and the mixture was still too rich at low revs when using the old needles and new jets, so I treated it to a new pair of needles, and the mixture is now too weak right through the rev range, with the needles wound up to the end of their travel.įloat levels were set as per the book, and the needles were set to 1.7mm below the bridge as measured to the recess in the middle of the jet (1mm measured from the step at the side)

Tuning stromberg 175 carbs