alenmatias
11.06.2021 1:19:14
Replacing the switches requires removal of the drive and bell housing.
These are the same procedures for replacing the Ujoint Bellows. [links]
See full version: Trim position sender and trim limit switches
Replacing the switches requires removal of the drive and bell housing.
These are the same procedures for replacing the Ujoint Bellows. [links]
The switches are prone to damage from water intrusion. Water enters the switch and ruins the contacts. The wires tend to soften and/or rot with age and water leaks into the switch through the wires.
Trim Sender Units
The trim senders are no longer sold individually.
The Port switch is the Trim Limit Switch. This limits how far up the drive will trim.
The Starboard switch is the Trim Level Sender switch. This sends a signal to the trim gauge.
The Trim Limit Switch prevents the driver from 'over-trimming" the outdrive while under way.
It is an important limiting feature which prevents damage to the drive and/or loss of control of the vessel.
Trimming the drive unit up too high while the boat is running can cause serious damage and/or injury.
When this switch fails, the TRIM BUTTON does not work. Only the TRAILER BUTTON will work. [links]
The Trim Limit Switch is mounted on the port side and the Trim Position Switch is mounted on the starboard side.
If one or the other malfunctions, you will need to get the entire Kit.
The Kits comes with both senders. The senders are pre-wired from the factory
with new wires.
Mercruiser did this because bad wires were the leading cause for switch failure.
Trim Sender Units
The trim senders are no longer sold individually.
The Port switch is the Trim Limit Switch. This limits how far up the drive will trim.
The Starboard switch is the Trim Level Sender switch. This sends a signal to the trim gauge. [links]
Replacing the switches requires removal of the drive and bell housing.
These are the same procedures for replacing the Ujoint Bellows. [links]
If one or the other malfunctions, you will need to get the entire Kit.
The Kits comes with both senders. The senders are pre-wired from the factory
with new wires.
Mercruiser did this because bad wires were the leading cause for switch failure.
The switches are prone to damage from water intrusion. Water enters the switch and ruins the contacts. The wires tend to soften and/or rot with age and water leaks into the switch through the wires. more
Alpha's and Bravo's have two Trim Senders.
They are mounted on either side of the Gimbal Ring.
One sender is for the Trim Gauge and the other sender is for the Trim Limit.
Then you run the drive all the way full down and check the sender so that it is showing full trim down on the gauge. If that is then set right you then use the trailer switch to trim the drive up until you have 18 5/8" measured from the center of the mounting pins at each end of the trim cylinders. Once thats right you put the trim limit on the gymbal ring and secure it. Run the drive full up (trailer) and see where your gauge is reading, run full down. The gauge should read full down. Run to full trim up and see when the limit switch limits the trim up where your gauge reads so you know that at that point thats where your full up trimed reads on the gauge.
ON my ALPHA ( 07 bayliner 185) when the drive is fully trimed "up" or "out" and hits the trim limit there is like only 4" between the end of the ram to the cylinder as shown as 6 1/2 +- 1/4 by the diagram. here
What you do is start with the trim limit switch set to where its at the point that it limits the trim pump from running at full trim up. ( you have the limit switch off the gymbal ring )
connect the trailer wire to the limit switch wire. You should be able to disconnect the wires coming from the trim limit sender. Then jumper the two loose ends together to bypass the sender. As long as the trim indicator is working you will be able to see how far it is trimmed without worrying if it's over trimmed.
unplug the harness, and test the hot coming from the engine in the plug . if it's hot through the harness, plug it back togeter, and check the wire at the end by the shifter. if it's not hot then there's a break in the harness. to test the switch, unplug the hot and touch the green or blue up and down. here
One may also ask, how do you test a power trim motor? To test the motor itself, bypassing the relays and relay wiring, find the two heavy gauge wires that lead to the trim/tilt pump motor. One should be green and the other blue. You will probably be able to find a quick disconnect plug near where the wires exit the outboard engine cover that you can disconnect.