WHAT IS NEUTRAL?

QUESTION: I am just getting into boating. I would like to know how to read drive and tab indicators. What are the neutral positions on the indicators?

ANSWER: When it comes to mechanical indicators on drives and tabs, there are at least a half-dozen brands, and that many more indicator cards. Some have numbers starting at zero and going up, and others count down from about three to zero, and then back up to eight or so.

Considering the varying systems and the human element of cable adjustments, the "neutral" position could be just about anywhere on your indicator.

So how do you know what the "neutral" position is on your drives and tabs? You will have to find out for yourself and mark your indicator panels. With the boat out of the water and on the trailer, use the trailer jack to level the boat. In most cases, using a level on the keel or chine near the transom will give you a good indication of when the boat is level. Then, have someone trim your drives to a point where the cavitation plates or propshafts are level (parallel) to the keel. The indicator reading at the helm with the drives parallel to the keel would be "neutral" for your boat.

The procedure is similar for the tabs except a straightedge is used to determine the neutral position. The tabs are considered at a "neutral" position when the bottom surface of the tab is parallel with the running surface of the bottom just in front of where the tab is mounted on the transom.

Most trim tabs are mounted about a half-inch higher on the transom than the running surface. If you place the straightedge on the running surface of the bottom just in front of the tab, and there is a half-inch gap between the straightedge and the tab near the transom, the neutral point will be when there is also a half-inch gap at the trailing edge of the tab straight aft. Once this position is attained, note the indicator reading at the helm. That is the neutral position of the tabs.

This procedure also will alert you if the indicator cables need to be adjusted. If there is a difference from side to side on the indicator panel when you have the trim at a level position or the tabs set the same, the indicator cables should be adjusted to result in the same reading at the helm. Be advised that there is a certain amount of slack in the indicator cables and that longer cables have more slack than shorter ones.

That being said, it is always best to approach a setting from the same direction. By this, I mean that you should trim both drives up to the desired checking point without having to adjust one back down. A minor adjustment in the opposite direction could result in no movement of the indicator because of the slack in the cables.

AMBIGIOUS TRIM

QUESTION: I have a 1995 Sea Ray with a 4.3LX Alpha One package. The boat is equipped with the Quicksilver 3000 throttle/shifter. The power trim button is very temperamental. Using the "trailer" switch causes the drive to go up with no problem, but the up/down buttons only work some of the time.

You have to toggle up and down several times, and then it will work. Is this a problem with the switch on the throttle, or should I be looking in the back end?

ANSWER: I would say that there is a 60 percent chance that the problem is in the switch on the throttle assembly. In order to resolve the problem if it is in the Quicksilver unit, you will have to replace the switch and check the wiring. But before you do that, check the connections at the trim pump to the trim limit switch that is located on the drive.

Make sure the connection is secure and absent of corrosion. The other strong possibility is that the trim limit switch mounted on the gimbal ring is defective. In order to test this, bypass the trim limit switch by connecting the two wires together that go to the switch with a jumper wire.

Generally, the wire looks like a black lamp cord and is plugged into the trim pump harness. Do not confuse the wire with the trim gauge wires, which are identical, but are usually connected into the engine harness that goes to the gauges. If the trim switch works correctly with the jumper wire in place, then it will be necessary to replace the trim limit switch on the gimbal ring.

—Need some guidance from Bob Teague, Powerboat's lead test driver and owner of Teague Custom Marine? To send him an email click here.

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