Tach acting weird

[JamesP]

I installed a new teleflex Tach a few weeks ago. (I have an Evinrude 140 and an OMC control box.) It acts fine in the lower RPM ranges but when it gets up to WOT at maybe 4500-5500 something goes screwy and the needle goes to zero until the RPMs drop back down... then the needle comes back to life and reads. Any advice on what happens to it in the higher ranges?

 

[Costa]

James what year model is your motor? Did you replace the tach because the old one was acting up also? get the model number of your motor and post your question on i-boats.com under the johnson/evinrude forum. there are alot of knowledgeable guys there that can help you out. If you have a looper style omc it more than likely is the regulator/rectifier that is a common problem on the loopers, but before jumping to conclusions get your model number and year model and work from there. Costa
PS you also might want to post this in the outboard forum

 

[happy]

i have a lil v mate.. with a 225 looper... tack acted up just like that so i put a new tac in.. then wound up having my o/b guy fix it... he put a key switch in it.. and told me to keep my hands off outboards...

 

[JamesP]

The engine is a 1985 140 hp V4. The gauges were replaced only because I liked the look better.