Trim Sensor Replacement 260 Merc/Bravo III

[Jimbo2624]

Well the trim sensors wires final met the end of life like so many others. I already have the outdrive off but the thought of pulling the gimbal and boot just to run the wires through the hull sucks, especially after I just replaced the boot last year. The design and routing of these wires is just down right stupid. Now that I have vented, I'll share how I'm replacing the trim sensors without removing the gimbal. I thing this method would work even if the outdrive was installed. I don't have any pics but here is how I got the old ones out (next post will report how well it went getting the new ones in).
1. Set-up your 1/4 drive with a couple extensions, you will need at least an 8" one to reach between the gimbal and the bolt that secures the wire clip.
2. Apply a little hand pressure to rotate the gimbal down as far as it will go. I have the trim cylinders off so it's easy.
3. Leave the socket off the 1/4" drive extension and it should just fit through the gap between the top of the gimbal and the transom mount.
4. Turn the steering so that the gimbal is rotated fully to stbd, this will create a decent gap on the port side. Using a long needle nose to hold an 11mm socket, install the socket on the 1/4" drive extension that's sticking through the top of the gimbal.
5. Holding the gimbal down, the 11mm socket will just line up with the bolt that holds the wire clip/ring and remove the bolt. It may be a little easier if you have a 1/4" wobble on the socket.
6. Enter the boat and find the leads coming through the hull and trace them out to disconnect. On my 260 Sundancer, the stbd sensor leads go to the harness near the trim pump and the port sensor leads go to the engine near the ECM control module.
7. Cut off the connectors so they go through the hole in the hull easy, but tie a long string on each set of wires. the string will attach to the new sensor wires to pull them through the hull.
8. Remove the two screws holding each sensor onto the gimbal. They will likely be hard to get out as the aluminum threads corrode. Soak with PB Blaster. Take your time and work them loose- your day will get long if you snap them off:smt089
9. Pull on the sensors and the rubber half seals should come out of the hull easy. Pull the wires to one side to remove the retainer clip. Continue pulling until the string is accessible.

I don't thing going back together will be so easy, especially making sure the half seals are seated. Getting the clip back on and the bolt back is going to be difficult, but doable. I will post how it goes. - Proteus

 

[BillK2632]

Yes, with some patience and every swivel socket know you can do this on a bravo, no way on a alpha.

 

[Bt Doctur]

In almost every case the wires deteriorate because of the constant 12v applied to the sender not to mention electrolsys. To help prevent this a simple wiring adjustment and the addition of 2 diodes solves the problem
You remove the 12v power that goes to the gauge and insulate it. Run a new wire from the gauge to the trim wiring at the control box.Using 2 1N34 diodes connected to the blue and green solenoid wires the other end of the diodes are connected to the new wire from the gauge.
Result is the trim gauge and the trim senders wiring only has 12v on it when the trim button is used.

To help prevent the transom seal from corrosion damage install the missing grease fitting

 

[bbwhitejr]

I replaced both pucks with OEM last spring w/o pulling the OD. It took about 2 hours start to finish and the wife's small hand to start the 7/16 head keeper bolt. Not that hard with a 12" extension.

Bennett

 

[Jimbo2624]

May I ask where/what grease fitting you are referring to? Thanx

 

[Jimbo2624]

Update: Success!! new sensors installed w/o removing gimbal. Installing the clip around the two wires took some time and patience. To get the 11mm bolt in, I put a little bit of white grease in bottom of socket to hold it. The one caution I will note is that if you use a ratchet to start the bolt in, be careful not to cross thread it. Also, make sure you see the ends of the half seals coming through the clip, then you know they are seated in the transom hole.

 

[Tripline123]

I know this is an old thread. But I have a 2003 Sundancer 260 and in the process of repairing my gimbal ring, bellows, and trim sensors. One issue I'm having since it is so tight in the bilge, does anyone know where the trim senders actually hook up to? I'd assume the trim pump, but don't actually know where.

 

[Bill Curtis]

Tripline123, Probably should start a new thread on this.

The senders don't connect to the pump. They actually have bullet connectors on them and the plug into the harness, which goes up to the helm. The stbd "Trim Sender" is for the trim gauge on the helm. The port "Trim Limit" goes to the throttle / shifter at the helm. It limits trim up and works in conjunction with the trim button on the throttle.

Do you have the Mercruiser manual for the drive? Bravo 1, 2, 3 Manual #28 shows it all and how to adjust them. If you can't find the manual, let me know. I have it on PDF.

 

[Tripline123]

Tripline123, Probably should start a new thread on this.

The senders don't connect to the pump. They actually have bullet connectors on them and the plug into the harness, which goes up to the helm. The stbd "Trim Sender" is for the trim gauge on the helm. The port "Trim Limit" goes to the throttle / shifter at the helm. It limits trim up and works in conjunction with the trim button on the throttle.

Do you have the Mercruiser manual for the drive? Bravo 1, 2, 3 Manual #28 shows it all and how to adjust them. If you can't find the manual, let me know. I have it on PDF.

Thank you. Yes, I have the manual showing how to adjust them. Just so difficult to get to anything. So found the port side hooks to two leads coming off the engine harness. The starboard side is now my issue, I have the cut end of the old sender but it looks like its either zip tied down behind the engine, so still trying to find out where it actually hooks/leads to. Its so tight that I have to lay on side of the engine, and get my arms back there to try and do anything. I now get why most boat mechanics weigh 140lbs. or less.