Tachometer Problem

[Argonaut]

My Maxum 1800SR3 has the standard Faria 0-6000 rpm rev counter ......... with a built in Hour meter.

End of last season the needle would often blip upwards .. as if jumping 500rpm .... but no change in actual engine revs.

This year it does not seem to be doing that, but now seems to be sticking .... i.e drop throttle and needle does not drop.

In fact on several occasions it is still reading 2000 rpm, with engine switched off.
if I tap the gauge gently the needle slowly drops down to zero.


I'm assuming this is pointing to a faulty gauge ? ......... does this mean I need to buy a new one.
If so anywhere particularly recommended to get one.
I am frequently in US on business, so could order one to be delivered to a colleagues for collection on next trip.

[CountryME]

You may just want to send it to faria for repair.

http://www.faria-instruments.com/sit...e_warranty.pdf

-JP

[dsbunton646]

Check the connections and the back of it to make sure they are secure and free of any corrosion. It may be a simple fix. If it works when you tap it, then maybe you will get lucky with a loose wire or some contact cleaning. If it is bad, then Faria will fix it under warranty as CountryME posted. Depending on how old the gauge is, will depend on if it is free or subject to a fee. Either way it is cheaper than buying a new one, but you will have to wait a few weeks for the repair. You can check "great lakes Skipper" and see if they have the gauge you need if you decide to buy a new one. I just bought a whole set from them a few weeks back. The entire faria set was under 300.00. Fyi the tach I bought had the hour meter as well.
http://greatlakesskipper.com/categor...xum-boats.html

[Argonaut]

maybe my description was wrong .... it works correctly the time, what is happening occasionally is when you drop engine reve ... its stays at previous reading.
Even with engine off it was reading 500 rpm.
It I tap glass needele drops with each tap ......... which I thought pointed to a mechnaical problem not electrical ?

[dsbunton646]

Probably you are correct with the mechanical problem from that last description. I found this on another forum, might be worth a shot as it sounds similar.
http://fletcher-boats.ning.com/forum...er-rev-counter

Or maybe this just to make sure that it is mechanical.
http://www.justanswer.com/boat/21zb9...-bowrider.html

Expert's Answer
Here is how to diagnose the tachometer. Note that most tach problems are sue to corroded connections, so check those first.



First, you will have to gain access to the rear of the tachometer. Keep all the wires in place and with the keyswitch in the ON position (Engine not Running) you must have 12 Vdc on the Battery + and Ground Terminals. If not, keyed power is not getting to the Tach.



If you do have the 12Vdc, start the engine (don't forget the cooling water) and take piece of wire about a foot long and momentarily touch the GROUND terminal to the SENSOR terminal, if the engine dies when you touch the terminals the Tachometer is BAD. If the engine continues to run when the SENSOR and GROUND terminals are touched, the wiring from the SENSOR terminal to the Negative side of the coil is not complete.



Does the needle deflect at all when you turn the key on? If yes, then:

1. Most tachs have a small switch on the back of the gauge that you set for the number of cylinders the engine has. You usually need a small screwdriver to push it in and turn it. Note the starting position and move it around a bit. These things seem to stick or corrode, often after storage. If that works, problem solved.

2. Using a 12v test light, attach the clip to a good ground and probe the terminal that has a grey lead on it - it will be labelled "tach" or "sig" or something similar. Engine on, the light should be rapidly flashing. If it is, replace the tach. If it isn't, that wire isn't providing a signal from the engine.



If there is no needle movement when you "key on", then you need to use the test light to see if the purple lead on the tach has power and if it doesn't, determine why.

You can also check the ground by clipping your test light to a known power source like on the power side of a fuse panel or circuit breaker, and then touch the light to the black or "ground" terminal on the tach.


745 days and 7 hours ago. Customer Reply
So there are two terminals on the back of the tach... one is the sensor terminal and the other is the ground....? want to nake sure I get this right....



So if I touch the sensor terminal to the ground terminal and the tach is bad, it will shut off the engine? Does this hurt anything?



When I start the engine, the needle doesn't move at all...... I have the wiring diagram for my boat. Grey wire from the tach to the engine harness......


Accepted Answer You may even find another terminal on the back for a lighted tach - it would provide 12v when the instrument lights are on. Grounding won't hurt anything - you just od it for a second anyway; you don't need to let the engine actually stop - you'll hear it. I'd bet on a bad connection - try unplugging and plugging the motor harness connector.

Expert: Captain Dave
Pos. Feedback: 98.6 %
Accepts: 2592
Answered: 5/1/2009

Marine Mechanic

[Argonaut]

Just thought I'd post follow up .... I tried all connections ... nothing wrong, contacted Faria .... they issued replacement gauge free of charge .... (via UK agents) so well done Faria.

[dronthelake]

I sent both my tachs to Faria to be rebuilt. I got what appears to be two new tachs back in 3 weeks. I am guessing but it appears they took my Maxum face out of the old gauges and put them into new gauges. The clear plastic front is new as well as the body. Now I am considering sending all the gauges in for recalibration.