Boat Maintenance Tips September '11

The majority of flats boats are equipped with a hydraulic system to raise and lower the engine on the transom. Our phone starts ringing when it quits working, especially if you're on the water when it happens.

There are four major brands of hydraulic lifts: Bobs Machine Shop, CMC Marine, T-H Marine and Detwiler Industries. All brands work on the same premise with a few design variations.

Troubleshooting:

Pump running but slide not moving. – Reservoir low on fluid. (Bobs and T-H Hydro-Jacker use 20w20 non-detergent oil. CMC, T-H Atlas and Detwiler systems use tilt/trim fluid.

Typically there are four wires in jack plate circuits. Red=positive. Black=negative. Green=down. Blue=up.

Beginning at battery; connections should be clean, shiny, and tight – nothing greenish or dull gray. Pull on wires to verify connections are not comprised internally. First component in line is a 40 or 50 amp circuit breaker that has a reset button on the side. If the circuit breaker is corroded, try jumping from one terminal to the other as a test to verify power to the system. Relays should click at this point when switch is engaged with jumper in place.

From the circuit breaker, the wires split and run two directions, the larger (10 gauge red) go to the relay pack and smaller (14 gauge) go to the actuator switch. There must be 12v power at the red or (sometimes purple) wire at the switch. If an inline fuse has been included it will be near the circuit breaker, always the center wire. Jump the center pole to either the blue or green and the relays should click or the jack should start moving.

The relay pack has two red wires for constant power on each relay (come directly from the circuit breaker). The smaller wires come from the switch. The wires leaving the relay pack feed directly to the jack plate actuator/motor and are susceptible to corrosion and failure.

Bobs jack plates have solenoids instead of relays but test the same way and have no splice between solenoid and jack plate motor assembly.

Remember, a clicking relay or solenoid is getting power but may not be transferring it. Jumping the large red wire from the battery to either the large green or blue wires at relays/solenoids should produce movement. Always check for fuel odors before jumping circuits. Fuel vapors in confined spaces can explode violently on the tiniest spark.

Relays and/or solenoids for up and down must be installed for test to be accurate. A basic 12-volt test light will make quick work of these procedures. Always start at the battery, keep it basic, and never assume.

Coastal Bend Marine
Port O'Connor, Texas
361.983.4841
CoastalBendMarine.com