When you say "clear" plug are you talking about an ivory colored nylon connector?
The trim/oil harness has two connectors at each end. One set of the harness connectors plugs into mating connectors at the engine side and the other set should already be connected to your tachometer.
Ten pin harness, remote oil tank harness, and trim/oil harness. That and the battery cables are usually all of the electrics that are used. Unles there is a standalone temperature gauge which also has a harness that goes to the sender.
Your motor might have a refrigerator white connector but if so that is for the Command Link connection.
-Maintenance is not a dirty word.
-The quality of a product may be directly related to the quality of maintenance given to that product.
-A coincidence that better maintenance = less manufacturing defects? I think not.