I get a lot of emails from folks wanting advice on this or that. And I don't mind. Far from it. I was a technical instructor for many years and still like teaching though I seldom get near a classroom these days. So it's fun. What I have observed recently however is an overreliance on the part of many on the factory manual. Now don't misunderstand. The factory book is indisputably the best book. The others, Clymer (ugh), Haynes, Cyclepedia etc. do an okay job (except the Clymer) but generally cannot be trusted where critical specifications are concerned. This is a well documented fact. Clymer for one has perpetuated misinformation about vintage Honda models for some 30+ years! Understand, no one reveres the book as much as I. How could I not be a champion of the factory document after over 200 factory Honda training credit hours, fifteen years in metro Honda dealerships, and my employment in the OEM corporate world ever since? The book is sacred.
But there are some things folks do not understand about the book, for example that it is not error-free. Pop your head up in the middile of your garage floor that has become suddenly and thoroughly soaked with shock fluid because you followed the manual's procedure on early Honda Pro-Link shock refresh, and you will realize this (rather intensely, I might add) firsthand. No one will have to convince you.
More importantly, what few outside the inner workings of the industry appreciate is that factory manual procedures such as resistance tests of electrical components are to be taken with a very large grain of salt. There are many reasons for this, such as the use of engineering data in the place of real-world findings, and the inevitable political manuevering within large corporations (giving us patently ridiculous instruction such as resistance test matrices for voltage regulators, something that happily, OEMs are just now beginning to recognize the fallacy of).
But the most insidious reason for manuals not being what they should be is this -- today's factory manuals are less tutorial documents than they are discovery documents. That's "discovery" in the legal sense. You see, starting at about the mid 1960s, manufacturers' books began to move away from being documents helpful to individuals, to documents helpful to corporations defending legal suits, until today that is their primary purpose -- to be literary bulwarks against the increasing tide of consumer irresponsibility. You thought manuals were for you. Hah! No way. They are CYA for the manufacturer, and have been for decades. Surely you have noticed that the factory service manual's close cousin, the factory owner's manual, has led the way in this literary nonsense until today it is a mere posting of eighteen ways to not swallow your key? Check it out. The service manual is not too far behind, demonstrating as it does less and less procedure (and that increasingly innane) and more and more policy. Policy that is defensible in court. That's its focus, and that is all the manual exists for, now, if you discount the specs content, which as I say should not be taken lightly. Sad but true. The factory service manual, anyone's -- Yamaguchi to KMW -- is largely and increasingly a legal preemptive tool, and little else.
So the next time I or someone else with real-world experience comes along and recommends technique that, though demonstratably effective, does not line up with the factory manual (for example, almost any electrical troubleshooting tip), now you know why. Don't get defensive or write them off as odd (though we may be that!). Realize they just may be giving you the best advice you are going to get. Think about it.