Gauges jumping around

[Jeepguy]

87 Procraft 1650v Evinrude 120. When running across the lake my gauges jump around when I hit the trim switch. Tach also seems to be reading low sometimes. I've checked all the obvious connections and such. Any suggestions?

[tj309]

Check the grounds. 90% of problems arise from poor grounding.

[olmo40]

TJ is spot on ,you may need to re crimp, wiring could be starting to corrode

[pyro]

It's common for the gauges to twitch when you hit the trim button. The hydraulic trim pump drawas a lot of current, which can cause the battery voltage to drop, momentarily affecting your voltage-dependent gauges.

Make sure the battery is healthy. A weak battery will dim your car's headlights when you turn the starter. A weak battery in your boat will make your gauges twitch worse when you hit the trim.

Also make sure the +12V wire from the battery that feeds the front end business is not used for other accessories that draw any decent power. Make sure the trim solenoids have their own large-gauge +12v wire coming from the battery.

I've seen one odd instance where someone had bypassed a bad trim solenoid and was running the (20 amp :eek:) trim motor directly from the throttle switch! Such a condition will PLUNGE the system voltage at the dash, due to resistive losses along the wire's length (this is why we use solenoids ;))