I've got twin 91 model Yamaha 130's (oil injected 2 strokes) on an older mako and have a problem that recently started. The starboard side motor RPM's will cut back (as if an alarm is in effect) after the engine has been running for maybe an hour or so, then go away, then come back, then go away again and so on. At some point the motor will just start running fine like nothing ever happened and I may not see the problem again the rest of the day. Seems to be an intermittant elect. problem of some sort and I'm having much grief trying to diagnose it. The motor idles perfect all the time, it doesn't seem to be fuel related as the other motor runs off the same fuel tanks and filters. One other thing, the digital tach shows no alarms when the problem occurs. The tach quit reading RPM's (shows 0 RPM's, but may read every now and then for a short time) a couple of years ago but this new problem just started less than a month ago. Very frustrated, any help would be appreciated...Thanks in advance.
