I have an 05 Honda 90hp, never had any problem but this past weekend looked at my tach and it was reading 6000rpm. I know the prop I have on would only turn 5400 with the load I had and the motor didn't sound like it was reving too fast so I didn't think my hub was slipping and after a couple of minutes the tach seemed to work properly. Could I have some thing loose or could it be electronic?

It is probably the tach itself or the sender. Bring it to a Honda dealer and have them test the motor. They should have a "boat in a box" that they can hook up to the engine a show the actual RPM's. More than likely you will need a tach.

Feel the lower back side of the tach. There's a switch there that may have moved. It happens.
Your engine should idle around 600-800 rpm.

Thanks, it only happened one time so far so I'll get it in to the dealer if it happens again.

I've often seen motors rev a bit higher when they pick up a weed or something else causing a little prop cavitation. Lose the weed or trim in a bit and the revs go down again. Could that be what you were seeing?

Unless the tach starts behaving strangely all the time, it is hit-and-miss whether a problem can be detected by shop-testing .

The engine wasn't over reving going by the way it sounded, it just seemed that the tach was giving a false reading.

I'd check you connections to your tach to make sure they're clean and tight.

My tach was reading high I sent a e-mail to the Co. Sent back was to remove tach rotate the setting screw a few times to clean off contacts, and reset to the proper place. It took about 5 minutes to do this and my tach is perfect. Not sure you have the same problems I had but it may be worth a try.

gdi

I'm thinking it is something simple and going to try checking it out this weekend.

look for aloose connection on the motor and also on the back of the tach.
just a thought