Found this post on ClassicMako yesterday.
its under their Motormouths section,,, called Older Evinrude Sanity Saver:
Just wanted to pass on a fix that had been eluding me for 3 yrs. I had a rough cold start/ non start issue with my 225hp 1989 rude. Ran perfectly after started. Checked grounds/wiring/coils/power pack / got new stator etc. etc. Finally discovered the shift interupter switch behind the linkage on the motor. It kills the 1-3-5 cylinder bank to slow the engine coming out of foward. It was intermittant, and was causing me to start the engine on 3 cylinders cold, which didn't always happen. If it fired the heat or vibration would free it up and it ran fine. Just popped it from its bracket to test, and motor fired up perfectly. Bought a new one but will probably not install it as it makes absolutely no difference in gear shifting on my motor that idles at 800. Motor heads may be saying DUH! at all this, but if you have similar issues, its a simple thing to check, which drove me crazy for quite a while. Good luck.