Tachometer fluctuates

[tripacer]

have a 1992 70 hp now that most of the electical problems seem to be straighten out
i need help with Tach issue ever since we have had this thing you can be cruising around at say 2500 RPM's the next time you look down the Tack is reading over 3000 RPM's you dont notice any RPM change but the Tack has changed then later its back to what it is supposed to be (???)
we have even had time were it will loose RPM's doing the same thing
This still has the VRO operational and is fucntioning well

Also what is the DO NOT EXCEED RPM's for this type of motor ??
Were do you Cruise at RPM wise

Thanks

 

[emdsapmgr]

Re: Tachometer fluctuates

Tachs are usually pretty reliable. You may have an issue with the rectifer. It charges the battery and also sends the signal to the tach.

 

[jonesg]

Re: Tachometer fluctuates

Check the wire lugs on the back of the tach.
I believe the max rpm is set in the power pack, usually around 5800 unless its a custom racing PP.
I go WOT to get out of the hole then chop it back to where it stays on plane and trim it out, never bother looking at the tach much.
A lot depends on the prop , hull design and weight load.