Everyone is always talking about EFI nowadays, and for an entire generation of racers and hot rodders there seems to be a lack of knowledge on how to tell what your engine wants if you don’t have an O2 sensor reading to go off of. You don’t have to have an electronically fuel injected engine to have an O2 sensor of course, and I would argue that it is a great tool even on carbureted cars, but it’s also a great idea to check out your spark plugs on occasional. If you run nitrous or boost, it is a smart plan to pull the plugs and check them after a run or dyno pull or whatever just so you can confirm the information the O2 sensor seems to be telling you. Or, if you don’t have an O2 it is a great way to get info on whether your engine is running lean, without enough fuel, or rich, with too much fuel.

In the video below the guys from Powell Machine are going to give a spark plug reading lesson while they tune something. It’s a single cylinder mini bike engine. Yep, you can read plugs in anything so this is a great engine to learn some stuff on and that’s why they wanted to share. So watch, and learn, and apply this to your own hot rod or race car.

Video Description:

In this episode we go over how to read sparkplugs for air fuel ratio, and we get Andrew’s mini bike carb dialed in.