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When I put throttle down from idling to get up on plane my tach bottoms out to 6000rpms. When at idle 1000 to 3000 rpms it reads fine. Anyone have any suggestions on what to do to fix. My boat is an 05 Nitro nx882. Anyone know what number settings should be on back of tach? Regulators problems?
Thanks Bassky
Has it always done this ? Or is it something that just started ?
It should be set at 6P or 6 pulses. If it asking for poles set it at 12 poles. If it just started doing this move the setting screw back and forth several times stopping on 6P. It must be exactly on. Close don't count as these are very small contacts in there. The reason for doing this is to clear any built up that may have accumulated on the contacts.
It did this earlier this year. I have only had the boat out once since then. Thanks I will try it tomorrow and see if it helps.
Bassky
While you have it open, check every wiring connection. Most gauges have little nuts holding wires onto studs. Tighten each one up. Be careful not to over tighten. I have found that this is biggest contributor to gauge problems, especially ground connections.
The tach feeds off a signal put out by one of the two regulators. You might try unplugging the gray wire that is connected to a regulator and plugging it into the other regulator. The charging systems really comes to life above 3k rpm. It may be that you have a failing regulator, which is pretty common with that design.
Here is an article I wrote years ago on iBoats. Keep in mind I have no experience with newer motors but the basics are still the same.
Your tach works off an AC pulse from the stator. You can take the rectifier/regulator out and throw it away and as long as the tach is connected to one of the yellow wires coming from the stator, it will work (if the stator is good). The connection for the tach is made at the rectifier/regulator simply because it is a convenient place to make it. The 2 or 3 yellow wires coming from the stator feed a full wave bridge rectifier consisting of 4 (sometimes 6) diodes. It depends on which diode gets damaged whether it will affect the tach or not. Bottom line is the charging system can be damaged but the tach still work. When in doubt, test your rectifier/regulator according to your manual.
Also if you have ever caused a spark or worse yet accidentally hooked your battery up backwards, there is a very good chance you damaged one or more of the diodes in the rectifier. This can affect the way your tach works.