"edolo" wrote in message
...
Friend claimed the used Scotty downrigger he had recently purchased
was running in reverse when he tested it. Suggested perhaps he wired
plugin in reverse, but thought no more about it. Last week he
discovered the Prawn trap puller also ran in reverse. He reversed the
wires & both dr's & puller ran okay. He next attempted to fasten the
Scotty (old style) plugin to the metal but blew fuses when the
negative made contact with the aluminum.

We tested using a digital meter & found downrigger wires & battery
both show 12v when grounded to boat. We ran the boat in the water &
did not observe any malfunctions. Also, the battery reads in the ull
charge range.

Removed all five sets of wires from battery. These we
Motor; power to console;downriggers; bilge pump; cigarette lighter
type plugin to console.

Tested each separately. Motor & power to console both showed 12 volt
when testing positive to aluminum. Downrigger ran correctly when
connected on their own.

The partics a 1987 Lund 16' aluminum with a 60 Hp Johnson 1989
CJ60TLCEA. The boat has apparently had wiring work done on it in the
intervening years & the problem appears to have surfaced only recently
when some wiring in poor condition was replaced.

My concern is that if he left thing as they are damage could at some
point be done to the stator. Before removing the console panel and
attacking the problem one wire at a time, I wonder if anyone has had
this problem & can suggest some shortcuts.
tks, edolo

Two problems. The battery Positive is connected to the hull. That is very
definitely wrong. And you should not use the hull as the ground / negative
for the electronics. You can see extra corrosion because of that. Run a
separate ground and power line to each device. Run the power from a good
fuse panel or circuit breaker panel. My consol electronics all have in line
fuses and run off a connector panel under the dash.