B275 problem with switch to alternator
Posted: Mon Sep 07, 2009 10:50 pm
a friend asked me for an alternator bracket for his B275 as he knew i had changed over my gas B414 over the winter. The blocks are the same on both tractors, even though the 275 is diesel, so the alternator mounts were thought to be the same. almost true, but thats another story.
switching from pos to neg ground should not be a problem with lights, glow plugs, or the starter or selenoid, or so i thought.
the starter uses a dyer(sp?) drive to manually engage the flywheel and connect a momentary switch that controls a selenoid to provide power to the starter(Lucas). a better system than a Bendix drive as it does not eat flywheel teeth. when switched to neg ground, the starter remained engaged in the flywheel after starting, causing the selenoid to smoke from the 100 percent duty cycle. replacing the old selenoid resulted in the same issue. switching back to pos gnd after alternator disconnect cured the starter engagement issue.
it doesnt make sense to me that the mechanical drive mechanism would remain engaged simply by swapping the polarity of the battery. any ideas?
switching from pos to neg ground should not be a problem with lights, glow plugs, or the starter or selenoid, or so i thought.
the starter uses a dyer(sp?) drive to manually engage the flywheel and connect a momentary switch that controls a selenoid to provide power to the starter(Lucas). a better system than a Bendix drive as it does not eat flywheel teeth. when switched to neg ground, the starter remained engaged in the flywheel after starting, causing the selenoid to smoke from the 100 percent duty cycle. replacing the old selenoid resulted in the same issue. switching back to pos gnd after alternator disconnect cured the starter engagement issue.
it doesnt make sense to me that the mechanical drive mechanism would remain engaged simply by swapping the polarity of the battery. any ideas?