Stopping engines
Now if you've got a smallish petrol engine (well, up to a couple of litres), you can stop it when it's idling by putting your hand over the top of the carburettor. This of course blocks off the air, and leaves you with a slight carb top-shaped mark on the palm of your hand, and a petrolly smell. It's quite safe because the engine is only turning slowly and the throttle is closed, so there's already a high vacuum in the carb and you don't increase it much.

A total mong that I used to work with tried this with a 4.5 litre diesel engine in a lorry which was running at a fast idle, about 1200rpm. the intake was the size of the palm of his hand. Oh, and because diesel engines don't have throttles but *do* have massive pumping efficiency (they suck lots of air through, which is why turbo-diesels are so good) they suck really hard.

I hit the "STOP NOW" lever on the injector pump within about a second, but that was long enough to turn his entire right hand into an enormous uber-hickey that swelled up to about 2" thick and purple.

This was not a pointless experiment, because he learned not to do that again, and I learned not to let him near things I was working on.
(gordonjcp, Sat 26 Jul 2008, 10:07, Reply)