Zombie Proof

The dead may walk. Carbon monoxide does not need their help, and it will not wait while you finish the sentence.
An engine is a controlled heat-and-pressure machine. The moment it stops being controlled, it becomes a metal grenade with opinions, and the opinions are not on your side. Everything after this page - the family tree, the jokes, the little program that draws a piston going up and down like a polite apocalypse - assumes you have already decided to remain alive. Read this once when you are calm. Read it again when you are not, which is when you will be tempted to skip it.
The rules that do not negotiate
Never run petrol, diesel, wood gas, charcoal gas, LPG, or any other combustion engine indoors, or in a garage that shares a wall, a loft, or a sense of optimism with a room where people sleep. "The door is a bit open" is not ventilation. It is a story.
Carbon monoxide is invisible, tasteless, and odourless. A certified alarm is a witness, not a permission slip. If it sounds, you leave. You do not lean back in to see which hose was feeling dramatic.
Do not improvise pressure vessels, boilers, compressed-gas receivers, fuel tanks, or high-pressure diesel injection. A boiler failure is not a comic beat. It is a wall leaving the building. In the United Kingdom, pressure systems above the relevant thresholds are expected to be properly designed, inspected, and fitted with relief, and to sit under a written scheme of examination. The spirit of the rule is simple enough to survive a grid: equipment stays inside its safe operating limits, and examination and repair belong to people who are actually competent. The apocalypse does not repeal that. It only removes the person who would have stopped you.
Do not run a homemade gasifier inside a building. Producer gas can carry a great deal of carbon monoxide, and if air leaks into the wrong place the mixture can go from "fuel" to "bomb"; without changing its expression. The forest is not a fuel until the poison has been taken out of it, and even then the work happens outdoors, upwind of anyone you like.
Keep ignition sources away from fuel vapour. Petrol vapour travels. It does not hover politely over the puddle, waiting to be introduced. A match in the next county of the workshop is still a match.
Shield rotating machinery. Belts, chains, flywheels, shafts, and fans do not distinguish between the undead and your fingers, and they are not impressed by either.
Wear the eye, hearing, hand, respiratory, and hot-work protection the job actually requires. Heroism is a poor glove.
The procedures in this book are educational. The manufacturer's service data wins every argument with a generic number. If this book and the manual disagree, the manual is right and the book is a well-meaning stranger with grease on its cuffs.
A sentence you can say out loud
Operate pressure equipment only inside its safe limits. Maintain it. Let competent people examine it and repair it. If you cannot name the limit, you do not have a project. You have a mood.
The zombies in these pages are a convenience. They stand in for hurry, folklore, and the part of a person that wants the engine to start more than they want to be there when it does. They are not the hazard. The hazard is the machine, the fuel, and the decision to skip a step because the street sounds busy.
If you remember one line from the whole manual, let it be the one on the sump, written first in grease and then properly: the dead may walk. The engine still needs oil. And it still needs you not to be in the room when it makes exhaust.