Re: 1999 4 STROKE MERCURY 40
Howdy, eskimo man.<br /><br />Welcome to iboats.

<br /><br />The first step is to get a Service Manual. It will answer the rest of your questions.<br /><br />I doubt that you can adjust the valve timing, which is set by the camshaft(s). I hope you are asking about setting valve clearance.<br /><br />If you will describe what is happening that makes you want to mess with the valves perhaps someone can help you deal with the problem.<br /><br />Good luck.
