LetsTalkSnow.com - Addict
Join Date: Nov 2007
Location: western Maine
I have a monarch pump on my dump body. You can test and get voltage, but you may be lacking in amps, that is, not a good current flow. Low amps will burn the motor, just like low voltage.
Try first thing running a jumper cable to put a heavy duty ground right to the motor body. The motor depends on good contact between the body and the frame of the truck. Corrosion or even oil if you sprayed the under body will reduce the contact. I can spray mine and the next day it won't go up or runs so slowly I know it will burn.
To fix that, remove the motor and clean the contact points (scrape and clean, add dielectric grease, maybe wrap some 12ga bare copper wire at the bolts/bolt holes).
There are filters in the fluid reservoir that need to be cleaned for good flow. Make sure the fluid is clean, cheap to replace it while you are in there.