Trim position sensor

[malrv1]

I have and old Mercruiser trim gauge that was running from a hydraulic trim sensor. Can I use this gauge (see photo) with the later Alpha 1 type gimbal mounted sender? I want to do away with the old hydraulic unit. Are the resistances different for the hydraulic and gimbal senders?

 

[Bondo]

Ayuh,..... Welcome Aboard,.... I believe they're the same,.....

 

[harringtondav]

Make sure your older gimbal ring and plate are set up to accept the electric trim/limit sensors. Each has a male 12 pt, shaft that engages the gimbal ring pivot pins, and is clamped with two tapped holes on the sides of the gimbal ring. Most important is the wire harness has a split seal grommet that is clamped into the gimbal plate above the drive shaft bellows. If your out drive doesn't have these features, you're out of luck.

If is does, prepare for a knock down, drag out installing the grommet harness. you'll have to remove the lower unit and bell hsg. to access the clamp bolt, and use a pivoting 7/16 GearWrench ratcheting box end on the bolt. The instructions are in the Sierra replacement kit. You'll need both the trim position and trim limit switches to get a full seal grommet, a helper and the Sierra gimbal pin removal tool.

 

[malrv1]

All OK with the gimbal it has the 12 point shaft. It already has a trim limit switch on the port side. I have it all apart to check and replace the bellows. The wiring is all rotted away so I will be able to rectify all that. I was just concerned about the ohm value of the switch compared to the hydraulic unit.

 

[harringtondav]

As Bondo said, most variable gage sensors (fuel level, oil press., temp., trim position) are the same. They output from near zero to 12 volts. The gages range from 24-300 ohm. See enclosed Merc. wiring diagram. The trim limit/trailer switch may be tricky depending on your boat's wiring. Merc & Sierra both recommend changing the trim sensors when changing the drive shaft bellows since it is such a pain to access the wiring clamp. Sierra 18-7633 Trim Sender/Limit Kit Replaces 805320A03

 

[malrv1]

Thanks for that. Just another question. How important is the cork gasket that goes between the inner transom plate and the transom. My did not have one at all.