Tacho not reading correctly

[Mike New]

I have a 2006 Monterey 194 fitted with a 5Lt GXi-F and have just noticed that the Tacho is reading iractically.
In fact at about 20Km/Hr the revs were indicated as being about 3,000!!
When I docked and set the engine to idle, the tacho showed about 1000rpm. I tapped the front glass and the needle fell back towards 500 (correct revs).
which indicated to me that the needle was sticking.
However when I again switched the ignition to run (did not start engine) the tacho slowly rose up to about 2500 and then fell back down to 500.
This would indicate to me that possibly I have a very expensive ECM problem!!! as I have never noticed this action before.
Has anyone else experienced tacho problems of this nature????

 

[dannys2004glastron175mx]

Its your tach mine was doing the same. I installed a new one it worked perfect after that :joyous:

 

[Mike New]

Thanks danny,
Spent time on the boat today getting ready to fit a set of SS exhaust manifolds, and noticed that the problem is still present, except this time the needle rose up to about 3000 before moving back to about 300.
I will fit a new tacho.

 

[Mike New]

I should have asked yesterday, Danny, What make of quality Tach would you reccomend?
An accurate tacho is important with a big engine, and mine didn't last long!!!

 

[dannys2004glastron175mx]

my boat came with Faria gauges so I jest replaced my tachometer with the same style .

 

[Mike New]

Thanks danny I was looking at VDO or a brand that is made in the US, the stuff that comes out of China still is not as good as it should be.
My SS manifolds manufactured in China for the designer, have pre threaded 1/2" pipe, boss's welded to them for the anodes. But they were not run through with a tap after welding, so guess what! neither of them will now allow the fitting of the brass anode carrier. They now have to be re-threaded.

 

[dannys2004glastron175mx]

yes any thing made in the US will be good :usa: , jest make sure what thread you need , pipe tread is different then standard coarse thread . like on a bolt