There are usually 2 paths 12v takes on a small boat once it leaves the
engine area. The first is thru a harness that probably has a plug on the
engine end. This set of wires runs your ignition, instruments, and anything
else that the boat mfr. deemed necessary to operate from the ignition
switch. The second path/s, which should be fused but often is not, runs
everything else on the boat. The origin for all of these paths is either the
+ battery post or a terminal on the starter. The common ground on your
engine should be a stud on the back side of a cylinder head or the -battery
post.

Your problem went from intermittent to solid. Did anything work right after
you changed the battery? Could you have left off a wire that should have
been connected to the battery?

Try this simple test. Turn your blower on and start wiggling all of the
wires that you can get your hands on in the engine room. If the blower
sputters or runs when you touch something, you have put your hands in the
problem area.

Some of the things that could be causing you grief are internal or external
corrosion of wire terminals ( particularly if they are steel). Corrosion on
the studs or posts they are connected to. A loose connection could lead to
arcing, which will cause a totally bad connection and or insulation melting.
A bad engine harness connection ( only if this is your only source of 12v
under the dash).

Good luck,
Jim
P.S. Keep a meter on your boat at all times.

"Inno" wrote in message
ps.com...
I have a 99 Larson with the Volvo 4.3 L 190 HP engine. When it starts
it runs quite well but today it seemed to be totally electrically
dead: no noise at all when trying to crank, no lights, no horn, no
blower, etc.

The battery is brand new (one day old), fully charged and the clamps
are tight. This has been an intermittent problem where I would let it
sit for a bit then it would be ok but today it would not show any sign
of electrical life at all. The positive cable seems to be tightly
connected down near the starter. I can't get at the neg. cable. The
fuses seem to be ok and if it was a fuse I would think that just some
circuit(s) would be affected and it would not be this intermittent
problem.

What should I be looking for that would shut down the entire elec.
system?

Please help! I am very far from any Volvo service shop and need to
fix this on my own. I am sure this must be something very simple I
do have an ohm-meter but it was at home three hours away today.

Any ideas would be much appreciated!