Exhaust gas analysis

I'd decided that although the B was MOT exempt now it had historic status, I wanted to get it MOT'd each year to be sure there were no issues I had missed. £40 to have a second set of eyes - and a proper look underneath on the ramps - seems like good value.

One of the things which I have always been conscious of is the emissions, so I thought some pre-testing might be worthwhile. I got hold of a Hawk Carburettor Fuel Air Tester which would help me get the carbon monoxide levels in the area of 3% at idle speed (which is the book spec).

You need to let the tester calibrate for around 8 minutes and also need to give the car a good run to get the exhaust up to temperature (the instructions say just running it on the driveway is not enough). So after doing this I hooked it up and was pretty surprised when the CO registered at 6.5% - very high and so very rich!

The Hawk has a remote pump which sits by the exhaust and accepts the feed tube from it. Long wires from that to the main box mean you can keep an eye on the numbers as you make adjustments.

I adjusted the carbs, checked again and repeated until I'd managed to get it down to sitting between 3.5% and 4%.

A test run showed no ill effects of the change and I probably imagined some peppier running.