As most know, I was having a problem with them randomly coming on around
2200 rpm. I changed the high pressure switch, and haven't -so far at least
- any repeats of the problem. Description of the procedure follows because
I found it necessary to make a special tool to do the job. Hopefully it
will save someone a lot of time and aggravation.

As for the oil light/buzzer problem, seems as though changing out the high
pressure switch did the trick. So far the light and buzzer has not come on.
I will say it was a bear to change, however. It went like this: loosen the
alternator and pull the belt back out of the way; next remove the coolant
pump pully - this provides access - sort of - to the switch. Remove the
wire from the switch. Weld a 3/4 in.  19 mm - (Wrench size) nut over the
socket hole of a standard 15/16 in socket. The socket will now fit over the
blade on the switch.  Turn the socket with a standard straight wrench. I
found I only had room to turn only one flat at a time. Remove switch and
replace with new. I found deep well sockets to long  and standard sockets
to short. The blade connection on the switch interfered with putting the
handle in the socket.

All that will get the job done. Don't forget teflon tape on the various
threads. The switch screws into an adapter pipe plug, and the plug screws
into the case. Both need the teflon to be sure of a seal. The switch should
also have an aluminum washer. If not present, get another switch.

Good luck to all who try this.

John