Mercury Trim Switch on Throttle Replacement

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Updated on July 25, 2023

The trim button on your boat is one of the most powerful tools. In general, the sailors think of the trim as only a way to tip your engine up and navigate through shallow water – which works well for that. The mind-blowing thing is that it is so much more – trimming the motor down and tucking it underneath the boat when you hit your throttle, an outgoing force that bows down like a lever arm.

Mercury Trim Switch on Throttle Replacement

The engine or the props is underneath the sail that introduces the bow to come down. Mainly, having enormous people on the boat, they will get a much better hole. Using a Mercury Trim Switch on Throttle Replacement allows you and your passengers to have a smoother ride depending on wave conditions and once you get used to it, you will realize that it is a marvelous tool – a discovery to do whatever you want by manipulating the boat entirely.

On the plane, people will probably notice that even your nose feels like dragging a little bit. An anticipated off the front is a splash, indeed present – this is the sign to use the trim accurately the opposite way. We need to start to feather the ornament/trim up a little bit at a time. 

Doing such steps, you will begin to feel the nose of the boat coming up. The drag quantity on the hull reduces by lifting the nose of the boat as the boat will go faster naturally. For instance, you’re in a choppy situation, and everyone in the boat is getting wet. The next thing is to lift the nose by trimming the engine slightly up as it terminates some sprays.


What is a Trim Switch?

A trim switch or hydraulic jack plate is a versatile switch. At the stern area of the boat, it provides a weatherproof control system. In position with one person, this is to facilitate the placing of the motor support. 

It is used when in the water with the engine in gear running – the trim switch on the throttle. To avoid over-stressing u-joints while running, it is designed to only go so high. On the other hand, when the boat engine is off, the trailer switch is used mainly. 

All the way, it is for pulling up to pull out completely of the water.

How does a Trim Switch work?

A trim switch of the boat activates the trim/tilt system which causes the outboard motor to raise or lower. There are three positions of the switch. It is for “Up”. “Down”, and “Off”. The center terminals function as direct or disconnect the electrical power.

What sends the power “Up” is the one set of terminals on the side of the trim/tilt system. Meanwhile, the power has been sent by one set to the “Down” side. “Off” is the central position.

What is the Mercury Trim Switch product? (description, features, and specifications)


A new OEM trim switch from Mercury Quicksilver is the boat part number 1075338 – its part number 87-8M0042300. It is indeed used on other boats commonly on tracer boats. 

This trim switch is made out of black-colored marine-grade plastic. Approximately, it measures 1 5/8” W x 1 1/8” H x 1 3/8” D (switch only) overall. It requires a 1” W x 1 1/4” H cutout.

Features and Specifications

It is sold as a single that includes (1) ON/OFF Rocker Switch and also (1) 3-Pin Male Spade Connector. Its boat manufacturer is Tracker and the part number is unavailable. Mercury Quicksilver is the part manufacturer and the part number is 87-8M0042300 – UPC; 745061440609. Its material is plastic and the color is black. 

The finish is Matte. Overall dimensions are 1 5/8” W x 1 1/8” H x 1 3/8” D. Whereas the cutout is 1” W x 1 1/4” H.

How to check the trim switch on a boat?


For testing of the motor itself, it is essential to bypass the relays and relay wiring. It will be introduced by finding two heavy gauge wires that lead to the trim/tilt pump motor. The colors available should be green and the other is blue. 

Finding a quick disconnect plug near where the wires are the next thing to do. This is where the outboard engine covers which you can disconnect. 

Steps in Replacing Mercury Switch Trim 


  1. Remove the shift/throttle lever itself, and you have a throttle only button at the pivot point of the handle
  2. Put the control in the full forward position.
  3. Now you can pry out the button.
  4. Then you can see the 11/16 nut that holds the handle on.
  5. Before proceeding, move the control lever back to neutral as it makes reassembly easier.


Other ways to replace the trim/tilt button on Quicksilver 2000 Commander


  1. Remove the whole unit from your bulkhead – it is secured by three bolts that pass through from the outside, and three undoubtedly hard-to-get-to nuts inside.
  1. With the control lever in the neutral position, undo that large central bolt shown in the first picture. Yes, that is the tip of its thread shown ringed in red and marked ‘2’ in the second picture. This will allow the whole arm to pull off – but it will be still connected by the trim switch cable.
  1. The red neutral-lock lever is held in place by a small bracket and two screws (13 & 14 in the exploded diagram). It will also have a spring fitted behind it, so take care as you remove it. This should give you access to the trim switch.
  1. You will likely also need to remove the unit cover – at least the lower one which is held by two screws – to get further access to the wiring.


How to replace power trim and tilt in a Mercury Outboard?


  1. Removing the entire trim until then the trim motor is what the mercury recommends – it lets a person do without removing the entire unit.
  2. Trim the unit up. Put the trailer down.
  3. The next step is to disconnect the battery.
  4. Also, disconnect the trim unit wiring from the connections under the cowling.
  5. Look at the eye of the trim ram – you’ll see a small pin that holds the pivot pin in place.
  6. Remove the pin then pivot the pin. It will allow the trim unit to tilt backward.
  7. Allow any fluid to run out by opening the fill cap.
  8. While holding the trim motor, remove the four screws.
  9. Replace the trim motor. Use a new gasket.
  10. Reverse the disassembly procedure.
  11. Refill the trim fluid.