Senders

As noted earlier, tracing the harness wires was difficult because they were painted over. A couple of hours with a continuity tester
and a wiring diagram revealed the position of the senders, two of which were missing. The temperature and oil pressure senders
turned out to be a problem. I made every effort to insure that the engine would be delivered with appropriate senders. When I
received the engine, it was apparent that the original senders had been removed by Mac Boring and replaced with plugs. Since I had
ordered the panel without full gauges, they took the time to remove the supporting senders and replace them with plugs. The plugs
had metric Allen-head sockets on them. I assumed that the pipe threads would be an odd metric size. I attempted to find out exactly
what I needed for senders. I must have made at least a dozen calls to the retailer and the distributor with no success. I finally decided
to just order the missing senders from the distributor. When they came in, I received generic Faria senders with no adapters. Neither
would fit and the oil pressure sender was the wrong resistance. I have no objection to Faria senders. The issue was finding senders
with the correct threads. I called the distributor again and reordered the senders. This time the temperature sender had the right
adapter, but the oil pressure sender wouldn't fit.

I removed the plugs from the engine and went down to Home Depot to see if I could find pipe fittings that would adapt the pressure
sender to my engine. It appears that the plugs are a standard US pipe thread, or at least the threads are close enough. Since the brass
pipe fittings are softer than the steel engine block, a slight difference in thread pitch won't cause a problem. I seated the pipe fittings
with a common pipe thread compound rated for gas and fuel lines. This will insure a tight seal. I could have ordered the senders when
I ordered the instrument and adapted them myself if I had known what to order. The oil pressure sender hole is a standard 1/2inch
pipe thread. The coolant temperature sender hole is a standard 3/8inch pipe thread.

The oil pressure sender is located on the side of the oil filter. There is insufficient clearance to directly fit the sender in the space
available between the oil filter and the fuel pump. I bought an elbow and nipple to allow the sender to be mounted at a 90 degree
angle.

The fuel tank I ordered comes with a fuel sender installed and adjusted by the fabricator. This sender is a standard American type that
is of the appropriate resistance to work with the Faria gauges I ordered.

Harness modifications were fairly straightforward once I traced out the harness. I removed the red ignition key wire from the back of
the starter and connected it the second alternator output. This will power the instrument panel from the house batteries. I cut the
white ignition wire and hooked it through the transmission neutral switch back to the starter solenoid. I cut off the connector used by
the oil pressure and temperature senders since my panel harness lacked the matching connector. I spliced in a four-wire trailer light
connector. Since I had two spare pins in this connector, I rewired the stop button wire (white/brown) to one unused pin and used the
remaining spare to power the smart regulator from the ignition key. I measured and cut the harness to the correct length for my
installation. All splices were done with a soldering iron and covered with heat-shrink insulation.

After completing the engine instruments and harness, I connected them to the engine along with a battery. I figured that it would be a
lot easier to fix harness problems in my garage rather than after engine installation. I was pleased that the panel light up and displayed
low oil and charge warning when the key was turned to the "on" position. I very briefly tuned the key to crank to see if the solenoid
would actuate. To my surprise, the engine started at once! Being accustomed to the unwilling behavior of my old W-60 to respond to a
start key, I had never expected the Yanmar to come to life. I had neither fuel supply nor cooling water connection. A quick press on
the stop button silenced the engine. After connecting fuel lines and a suitable cooling water supply, I ran the engine again and verified
that the tachometer and oil gauge worked. I didn't run it long enough to verify operation of the temperature gauge, nor did I check
the auxiliary alternator.