1985 mercruiser trim pump on a 1985 140

[Ed Harris]

The engine is a 1985 140 and after letting boat sit for a couple of weeks ( I currently have 2 boats) the trim pump motor will develop a scale between the brushes and the copper end of the armature. Is there anyway to keep this from occurring other than running the trim pump once or so per week? Or is it time for a new pump motor. It’s a hassle to pull the pump and take it apart to sand off the the scale. Original engine still runs great.

 

[Bondo]

the trim pump motor will develop a scale between the brushes and the copper end of the armature.

Ayuh,.... Is the motor gettin' wet,..??..??

 

[Ed Harris]

It may have. Sometimes on a hard rain my cover will fill up but it’s not like it’s in direct contact with the rain. It is covered by the motor cover/ rear seat. I will try and cover with a plastic bag when not in use and check.

 

[Tycer]

Was this ever in contact with salt water? If so, maybe flush with salt away.
Most emery cloth has metal in it and should not be used on commutators. It might lead to some arcing and more contamination. Any good spray contact cleaner can clean between the slot bars.

 

[kenny nunez]

Next time you remove the brush head, remove the springs and gently stretch them. Make sure there is no corrosion on the outside of the brushes. Put a small dab of grease in the brush holders. Take a 4” piece of coat hanger wire, bend it into a “V” shape. Put the springs and brushes in their holders then install the “V” between the brushes to hold them. Do you still have the small ball bearing on the end of the armature? Drop the brush holder over the armature then pull out the “V” shaped wire. This is the way I found that worked and kept the brushes tight on the armature. As you said keep the motor covered which should also help.
If the armature is smooth with no burned or “high spots” you should not have any more problems.
I used this method many times when I had my shop.