How to check a rectifier?

[flclexsc]

I have a 1994 c115 yamaha that has no spark. I followed the info in the manual about checking out the rectifier and I'm not sure if I am doing it correctly or not. To me checking for continuity means putting my meter on the continuity setting and listening for a beep. When I do the check I don't get a beep but I do see very high resistance ~ 12-15 mega ohms. Is this right or should I be seeing infinite resistance? Is this perhaps an indication the rectifier is breaking down?