The trim angle of the outboard motor helps determine the position of the bow of the boat in the water. Correct trim angle will help improve performance and fuel economy while reducing strain on the engine. Correct trim is angle depends upon the combination of boat engine, and propeller. Correct trim is also affected by variables such as the load in the boat, sea conditions, and running speed.
Adjusting trim angle for Manual Tilt Models
There are 4 or 5 holes provided in the clamp bracket to adjust the outboard motor trim angle.
1. Stop the engine.
2. Tilt the outboard motor up, and then remove the trim rod from the clamp bracket.
3. Reposition the rod in the desired hole.
To raise the bow (“trim-out”), move the rod away from the transform.
To lower the bow (“trim-in”), move the rod toward the transom.
Make test runs with the trim set to different angles to find the position that works best for your boat and operating conditions.
- Stop the engine before adjusting the trim angle.
- Use care to avoid being pinched when removing or installing the rod.
- Use caution when trying a trim position for the first time.Increase speed gradually and watch for any signs of instability or control problems. Improper trim angle can cause loss of control.
The outboard motor trim angle can be changed approximately 4 degrees by shifting the trim rod one hole.
Adjust Boat Trim
When the boat is on plane, a bow-up attitude results in less drag, greater stability and efficiency. This is generally when the keel line of the boat is up about 3 to 5 degrees. With the bow up, the boat may have a greater tendency to steer to one side or the other. Compensate for this as you steer. the trim tab can also be adjust to help offset this effect. When the bow of the boat is down, it is easier to accelerate from a standing start onto plane.
Too much trim-out puts the bow of the boat too high in water. Performance and economy are decreased because the hull of the boat is pushing the water and there is more air drag. Excessive trim-out can also cause the propeller to ventilate, which reduces performance further, and the boat may “porpoise”(hop in the water), which could throw the operator and passengers overboard.
Too much trim-in causes the boat to “blow” through the water, decreasing fuel economy and making it hard to increase speed. Operating with excessive thrim-in higher speeds also makes the boat unstable. Resistance at the bow is greatly increased, heightening the danger of “bow steering” anf making operation difficult and dangerous.
Depending on the type of boat, the outboard motor trim angle may have little effect on the trim of the boat when operating.
Tilting Up and Down:
It the engine will be stopped for some time or if the boat is moored in shallows, the outboard motor should be tilted up to protect the propeller and lower casing from damage by collision with obstructions, and also to salt corrosion.
Be sure all people are clear of the outboard motor when tilting up and down, Body parts can be crushed between the motor and the clamp bracket when the motor is trimmed or tilted.
Leaking fuel is a fire hazard. If there is a fuel joint on the outboard motor, disconnect the fuel line or close the fuel cock. If the engine will be tilted for more than a few minutes. Otherwise fuel may leak.
- Before tilting the outboard motor, stop the engine. Never tilt the outboard motor while the engine is running. Severe damage from overheating can result.
- Do not tilt up the engine by pushing the tiller handle (if equipped) because this could break the handle.