7.4 merc. Questions, inboard, needle questions

[chipraynor]

I have a 31 sport craft express with 2 merc. 7.5 horizons. Full inboard, my questions are:

My RPM gauge needle sticks in a few spots..how can I fix that…

Does the rootery cap and rooter have anything to fo with the RPM reading..is that something I should change…it’s very minor. And Yes when I tap on the glass gauge it also jumps..

[Capt Kid]

the grey wire from your ignition coil should control the rpm gauge. the gauges are notorious for getting moisture or condensation into them and effecting the "signal" from the grey wire. if it were mine i would check all connections and if that dont work replace gauge

[master wrench]

As stated I am thinking you need to replace the Tach in the dash. Over time moisture and getting bounced around takes its toll on them.

[bottom scratcher]

If it's a teleflex, there's a known issue with them. Go to the back of the gauge and look at the switch that selects the number of cylinders. If it has one, slide the selector back and forth. It has corrected the problems on those models that have the slide switch.