Tach drops to zero

[tampaskiffer]

I have a 2000 40hp johnson and have a omc tach that idles fine (800) until throttled up. Than it drops to zero and stays there until brought back to idle. I have ck'd all grounds and ck'd to see if I am charging 12volts while cruising. According to volt meter the stator is charging. I have read somewhere that adding a 1/2 watt appx 2000 ohm resistor between sender and ground terminals(on tach) that this would resolve the issue. Anyone have any luck with this or had the similar problem? Thanks ya'll. Jeff(tampaskiffer)

 

[Steve135]

Re: Tach drops to zero

If your only charging at 12 volts I would think its the rectifier as your motor has a non regulated systems and should be at 13.8 volts when crusing. Did it just start doing this?

 

[steamboatwilly]

Re: Tach drops to zero

The Teleflex tach.manuel says if idle rpm is ok but throttle up and tach.rpm goes to zero, then is possibly the rectifier is bad.

 

[tampaskiffer]

Re: Tach drops to zero

Im sorry the volt meter does go above 12 volts while cruising. What other symptoms might I have if the rectifier is bad? I would hate to replace it and still have a tach problem.Thanks Jeff(tampaskiffer)

 

[steamboatwilly]

Re: Tach drops to zero

Teleflex says,Rectifier may be chargeing battery but still could be bad.