Author Topic: Tachometer jinking around  (Read 320 times)

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Offline metalwrkr

Tachometer jinking around
« on: May 18, 2017, 09:26:22 AM »
I have a 2005 Honda 90 in real nice shape.  Yesterday starting out I noticed my tach RPMs jinking around up and down even though the revs were steady at cruising speed.  The needle would jump from 4400 to 5000 to 3800 to 5400 all over the place.  it would settle down and star jumping again.  After a short time it settled down and worked fine.  The culprits are obviously; gage, wiring or sending unit where ever that is.  I will start by cleaning all contacts and spraying moisture displacement on them but where to go from there?  Anybody had this problem?  How would you troubleshoot this?  Thanks.......Russ K. 
metalwrkr:  Sent from my rotary phone.  I have two speeds; Dead Slow and All Stop
05 17SR
06 Honda 90
2016  Honda 8 kicker
05 EZloader oil bath

Offline Hydroman

Re: Tachometer jinking around
« Reply #1 on: May 18, 2017, 10:14:29 AM »
On many tachs there is a selector switch (may be under a small plug) to match the tachs to a specific engine. 

Just rotate the switch several time and it may wipe the contacts clean. Make sure you check the as found position so you make sure it get left in that position.

Jim
17 Sea Chaser (sold)
21 Skip Tower (sold)
27 Thunder Jet OS

Offline Threeweight

Re: Tachometer jinking around
« Reply #2 on: May 18, 2017, 10:20:59 AM »
If it worked fine previously, his tach is likely already matched to his engine.

I would suspect either a bad ground, or bad wiring.
Former Sea Chaser 17 owner
Wild Card, Hewescraft Ocean Pro 220, Honda 225 and 9.9

“Never turn your back on fear. It should always be in front of you, like a thing that might have to be killed.”
       --- Hunter S. Thompson

Offline Diablo

Re: Tachometer jinking around
« Reply #3 on: May 18, 2017, 12:38:35 PM »
Tack signal comes from the alternator. Check your connections there and at the tack for tightness or corrosion, clean and tighten. You could also be having indications of a part that is failing. Good luck.
'98 19SR  '15 E Tec 115, '10 Honda 8
'88 17SR  '90 Johnson 90, Honda 8, SOLD

Offline Hydroman

Re: Tachometer jinking around
« Reply #4 on: May 18, 2017, 12:56:47 PM »
Threeweights,

 I realize that the tach worked previously.  However it is no uncommon for the contacts in the selector switch to develop a poor contact over time from moisture and just be subject of bouncing around.

Jim
17 Sea Chaser (sold)
21 Skip Tower (sold)
27 Thunder Jet OS

Online Chief of the Boat

Re: Tachometer jinking around
« Reply #5 on: May 18, 2017, 03:56:48 PM »
Do you have the standard analog Honda tach with an hour meter?   I agree with Jim on the contacts on the selector switch corrosion under the cowling.
 :twocents: 
1994 Sea Explorer 1511 loves whitecaps 2010 Yamaha F-70 2012 Yamaha F-8 with a  Fixed SaltBoss Bracket Lowrance HDS-5 & 7 Gen 2 Standard Horizon Fixed VHF 2150 with AIS

Offline DevMah

Re: Tachometer jinking around
« Reply #6 on: May 18, 2017, 07:31:46 PM »
All the info so far sending you in the right direction....


The black wire on your tach is B- the black yellow switched 12v B+ and the gray goes to the regulator/rectifier.

Check you connections at the gauge and the connector at the engine.
 It is possible that you may have loose/bad connections, broken signal wire a failing tach or rectifer.

Dev
2015 21' Sea Ranger
2015 Yamaha F150
2013 Mercury 9.9 Bigfoot 4 blade
2012 Lund 1650SS  w 2012 60HP Mercury-Sold

Offline rasslingref

Tachometer jinking around
« Reply #7 on: May 18, 2017, 09:56:23 PM »
My 1999 Honda 90 does the same thing. I have a corroded connection at the gauge but I'm too lazy to fix it. It's the ground  wire that gets corroded and I finally found the source for the water coming into that area. Horn cover leaking.   Hehe
OK so I did fix it but I'm still lazy.


Sent from my iPhone using Tapatalk
1998 19' SR HT 1999 Honda 90 Yamaha 9.9
Kitsap County, WA

Offline metalwrkr

Re: Tachometer jinking around
« Reply #8 on: May 20, 2017, 08:33:52 AM »
Was finally able to get in touch with my "ACE" Honda tech late Friday.  He said this is a common intermittent problem with the causes from most to least probable being: moisture on contacts, corrosion on contacts, bad corroded or incorrect wiring and last, failure on the sending side (engine).  Solution: clean all contacts both at the gage (this includes rotating the tach selector switch) and engine (there is a junction box at the engine) and any junctions or fuses in line.  Spray these connections with moisture displacer/ corrosion block.  Run the boat and hopefully the problem is solved.  If not, beg borrow or creatively acquire a temp tach that works and hook it up and run the boat. If it works correctly then your original tach is bad (don't forget to return the borrowed tach). This procedure will solve 90% of the problems and is fairly owner friendly to do.  If there is still a problem and you are not a more advanced trouble shooter, his suggestion is to bring the boat in for service.  All his info seems to jibe with forum input.  I have now done all the cleaning and spraying but have not had a chance to retest.  I guess another fishing trip is in order.  Thanks for all the input and Rasslingref you really should jump on that fix!.....RK
metalwrkr:  Sent from my rotary phone.  I have two speeds; Dead Slow and All Stop
05 17SR
06 Honda 90
2016  Honda 8 kicker
05 EZloader oil bath

Offline Foxsea

Re: Tachometer jinking around
« Reply #9 on: May 22, 2017, 01:11:38 PM »
Mercury outboard I had with that issue, found out had a bad voltage regulator. Another option to check.
Foxsea


2015 21ft Sea Explorer
2016 150 Etec

Offline milos dad

Re: Tachometer jinking around
« Reply #10 on: May 22, 2017, 01:37:01 PM »
The Honda tach on the Arima I bought had the needle jumping around when doing the river trial.  Dealer replaced the tach and it has worked fine since.

M D
Rick
87 Sea Hunter with 94 Honda 45
2009 6 hp Merc kicker