Tach Problem

[wiggreb]

I have a Trophy 19ft center console with a Merc 125. It was about a year old when I bought it, and I've had it almost a year. When I got it the tach seemed to work fine. Then the needle began sticking. I could thump the front of the gauge and this would seem to "fix" the problem for the time being. Now, it is stuck in one position and I cant get it to move. I tested the gauge using a procedure I found from reading this site and it didn't work the way it was supposed to. Any suggestions? Should I just buy a new gauge?
Also, the temp gauge didn't seem to be working either. I tested it in the same manner and it did what it was supposed to. However, when running the motor, it never seems to move at all.

 

[Laddies]

Re: Tach Problem

You need a new tach

 

[Texasmark]

Re: Tach Problem

The tach needs 12v and gnd to operate. The Quicksilver tachs which I am aware of have a quick test to see if they are "ready to work".....not necessarily working.

The tach stops at the last rpm it was recording when the ignition key was turned off....so it may be sitting anywhere; usually under 1000 rpm's as you were at idle when you killed it.

Upon turning the ignition key to RUN, the needle is to position to 0 - 50 rpm's (right outta da book)...yeah I know 50 rpm's is hard to see on a 8000 rpm instrument, but the point is, it needs to be driven from where it was sitting to 0.

If it doesn't zero, then as Laddies said, get another.

But if it does, then the trigger pulses from your rectifier/regulator could be defective which would cause an erroneous rpm reading.

Son and I are currently in the wait and see mode on his. He just bought the rig and the tach wandered.....it passed the O start test however.

The engine is a 150 and has 2 separate rect/regl modules, each with a separate stator to feed it and a tach output. Tried swapping modules and didn't seem to solve the problem.

Bought a new tach ($88 from local Merc dealer....Quicksilver brand) and installed it. Have not been back to the lake to test it.......we'll see.

Mark

 

[Silvertip]

Re: Tach Problem

How does the scale on your temp gauge read? Some ae C-N-H (cold-normal-hot) and others have numbers. If your gauge reads 120 on the low end of the scale, its not a good gauge for an outboard as under normal conditions they don't run much hotter than that. If the bottom numbers are 60, 80, or 100 then that's the correct gauge. The thermostat may be stuck open in which case the engine will run cold, or the sender may be bad. The sender can be tested with an ohm meter a pan of hot water, and a meat thermometer. If memory serves me right, the sender should read 600 - 1000 ohms at room temperature.

 

[wiggreb]

Re: Tach Problem

The lower end of my temp gauge is 120. (it has numbers). Why would a manuf. put a gauge on there that is not compatible with my outboard? That's pretty goofy.
As far a the tach goes, I'll have to see of it "zero's out" the next time I start it.

 

[wiggreb]

Re: Tach Problem

The lower end of my temp gauge is 120. (it has numbers).
Correction: lower number on temp gauge is 100.