tach

[sparky]

So here's a "what do you think it is" question...Have an '05 1800 sr3 with 4.3ltr....My tach is the 6k OEM one with hour meter on it made by faria....Anyhows every now and then I'll start the engine and it shoots up to 3k rpms at idle...When I start running the boat the gage is 3k off on the rpms as if the 3k mark is the zero point...So i'll stop turn off ignition and watch the needle go down to zero slowly and restart and all is ok...

It seems to do this about every 3rd or 4th time I start the boat...Whats ya all think??? I layed down on the floor and looked under the panel and shot a flashlight up there and all seems tight and non corroded, quite clean really....Hmmm

[jamanati]

Just tap on the tach a bit. Many tachs have this problem, they just get old. If it doesn't correct itself, time for a new tach.

[biggerseagar]

Dido....same on my 3000....just tap the face and it will go back to normal.....

Roger

[pascavone]

do you have a radio speaker, garmin, or Ipod with a magnet close by to it?

question is, is the engine at idle 800 rpm?

go to autozone and buy a $20 tach and wire it in and run them both to bench test the old one.

a 2005 engine has the NYAC sensor that control the air valve flapper, which sets your idle.

if the sensor is shot, you will see unresponsive RPM control from the cold start knock down, and when you pull off plane quickly.

Like an airplane, you must always trust your gauges.

[sparky]

thanks for the responses guys....