Tach Stoped working

[Johnson 90]

i have a 89 johnson 90 hp vro outboard while out fishing the other day the at about 800 rpm the tach started to bounce between 800 and 1500 rpms for about 1 hr then stoped working. i have been out several times since then and it does not work at all. and there doesn't appear to be anyother problems with the motor or boat. battery is charging fine all other guages work fine. any one have any ideas on what my problem may be and how i could go about testing and correcting it.<br /><br />thanks <br /><br />adam

 

[R.Johnson]

Re: Tach Stoped working

Test between the gray, and black leads going to the tach. You should have 9, or 10 volts. If you do! the tach is bad.

 

[Johnson 90]

Re: Tach Stoped working

if i don't??

 

[R.Johnson]

Re: Tach Stoped working

Test the rectifier.

 

[Johnson 90]

Re: Tach Stoped working

sorry let me back up a little with a dumb question first should the motor be running to get that reading.

 

[R.Johnson]

Re: Tach Stoped working

Yes? the motor has to be running, The tach, signal comes from the alternator.

 

[snagroms]

Re: Tach Stoped working

I would also suggest when checking voltage that you remove each wire from the terminals and thoroughly clean them. Make sure they are tight when you put them back on. Find the other end of the wires and do the same. Don't forget include the large connector for the engine harness to cover the grey wire.

 

[dougmn]

Re: Tach Stoped working

This happened on my 1996 88spl. It was caused by a bad horn.Yes the boat horn.Dougmn.

 

[Johnson 90]

Re: Tach Stoped working

dougmn how did you fix that because the same time the tach went. the horn stoped working right. do i need a new horn or is there a way to just disconnect it

 

[dougmn]

Re: Tach Stoped working

I bought a new horn from one of the mail order places.Never tried just disconnecting it,Because I was just trying to fix the horn,the fixed tach was just an accident.Doug