Old Trolling Motor Repair

Return to Mark’s Pages

My trolling motor from the late ‘80s. Hardly used and kept in its box until Harvey. The top doesn’t look too bad but lots of very rusty water came out of it. Mainly from the tube to the motor.

The bottom unit was a different story. Full of rusty water and “rust mud”.

The switch tests out for continuity for the different positions. So far so good.

The inside of the head was not bad…

Bottom end is a mess. Armature is coated in “rust mud” and the internals on the housing also covered. It’s a mess.

Close up of the commutator. Needs a lot of work.

Cleaned up the brushes.

Time to service the armature. Wrapped in cloth, stuck in a rubber boot and then clamped in a vice. Cleaned and polished the commutator bars and checked the circuits.

A “too short” wire snapped off from this brush conductor to the field…

Resoldered with a short extension with shrink tubing. Ready to reassemble.

This turned out to be very tricky. Had to load those springs and then the brushes into their holders and then insert the armature assy and then get the brushes onto the comm bars.

Took a couple of hours to get a solution. Two small needle nose vice grips holding each brush compressed while putting the armature through. Then when the comm bars were in  the brushes far enough, pulled out each vice grip and the brushes snapped into place. Whew!

Torqued the housing closed to spec. Prop on and bottom end finished.

Ready to test. Because there -could- be a short or some other mistake I could have made, am using an old electronics tech trick called a dim bulb test. In the circuit with the motor I used a 12v car bulb. If there is a short, the bulb provides resistance and does not allow damage. So with the motor switched off, the bulb was out. If there had been a short, it would have glowed brightly. And as I switched the motor to different speeds, the bulb glowed at various amounts of dimness. Note: the camera makes the bulb look bright. It is actually dim in this picture.

video

See more of Mark’s projects here.

Leave a Reply

Your email address will not be published. Required fields are marked *