Here's one for you all. I noticed a few weeks ago that my 90hp merc wouldn't idle well. Idle a few minutes and sputter and go dead. I thought that it was time for some work. Sunday I went out and the engine wouldn't start. Put the spark tester to it and bam good spark. While I had the cowling off I noticed that all the plugs were loose. I tightened the plugs and still wouldn't start. Turns out it was cold and the primer ball was stiff and I didn't prime it good enough. After starting it it idled perfect all day. I must have not tightened them after the last compression check. For me in most cases the problems that I have are usually something really simple like that. A loose wire, a loose nut, a loose plug, will give you fits. Hope that helps someone.