1995 Evinrude 88hp tach erratic reading

[imported_Chuck]

I had a new Farina tachometer professionaly installed last year with no issues. After our first run over the weekend, the tach would get up to 4200 RPM and go to "0". We'd re-start and run at low RPMs with no problems, once advancing above 4000 RPM the tach would act erratic and crash back to "0". Any ideas how to trouble shoot??? Bad Tach or electrical issues???

 

[jtexas]

Re: 1995 Evinrude 88hp tach erratic reading

Rule out alternator/rectifier fault by checking the battery charging voltage when the tach zeros out.

 

[tashasdaddy]

Re: 1995 Evinrude 88hp tach erratic reading

dirty connection get hot and opening., rectifier failing.

 

[ezeke]

Re: 1995 Evinrude 88hp tach erratic reading

Start with checking all of the connections for corrosion.

Be aware that Teleflex has the following message with their installation instructions: ​

"Johnson/Evinrude 88-112 hp SPL ?Special? models may require the addition of a 2000 ohm resistor or a BRP voltage regulator."

See page 7 here: http://www.downloadingfiles.co.uk/t...structionmanuals/99320 rev 10 Tachometer,.pdf

​

 

[jurgenscraft]

Re: 1995 Evinrude 88hp tach erratic reading

Good evening all.
I agree with the post that says CHECK ALL CONNECTIONS that is exactly what I found a loose wire connection on one of the terminals at the back of the tacho.I then checked all connections and all was well again,
Regards William Wright

 

[kjshunter]

Re: 1995 Evinrude 88hp tach erratic reading

Mine is doing the EXACT same thing on my 88 spcl. It's a new teleflex tach. I have the pole ajustment on the back at 6-p, so maybe it's a loose connection or something.
Works great untill about 4000 rpm's then falls to 0. Back off the throttle and it picks back up... weird.

 

[kjshunter]

Re: 1995 Evinrude 88hp tach erratic reading

#Chuck...let us know what you find and I'll do the same so maybe we can help each other out. Checking all the connections first. I looked on Teleflex's websight and the model of guage I have is one they reccomend for V-4 i/o's, it is a 0-7000 guage, the outboard model is a 0-6000 rpm guage. The guy at the marine place said it didn't make a diff. But he might be wrong. I talked to a instrument tech. at work, and he said a frequency meter would help to pin point the problem.

 

[kjshunter]

Re: 1995 Evinrude 88hp tach erratic reading

Got mine working. Bad connection on the grey wire comming from the motor. I also got an email from Tele-flex that said the same thing as above. It said on the 48,88, &112 spcls, (Jon & Rude) there is no voltage regualor, and thus a 2000-2200 Ohm resistor connected from the send (gray) to the ground (black) terminals on the tach will alleviate the eratic tach issue 90% of the time. Considering your rectifier is good that is.