Frequently Asked Questions:

Outboard Questions

 

Q:
 		 3 Blades.... or 4?
 
A: We recommend 3-blade propellers for recreational boats with 3, 4, and 6 cylinder outboards and I/O engines. These propellers provide good "hole shot" and top-speed performance.

We recommend 4-blade propellers for bass boats and boats with high performance hulls running high horsepower outboard engines. Compared to 3 blades, they provide better "hole shot" performance with less steering torque and less vibration at high speeds.
Q:
 		 What's the advantage of a left-hand prop?
 
A: Two propellers spinning the same direction on twin engine boats will create steering torque. In other words, two right-hand propellers pull the stern hard to the right and the bow to the left.

Two opposite-direction propellers on twin engines eliminate this sterring torque because the left-hand propeller balances out the right-hand propellr. This results in better straight-line tracking and helm control at high speed.
Q:
 		 Aluminum vs. Stainless Steel?
 
A: Most pleasure boats are factory equipped with aluminum propellers. Aluminum propellers are relatively inexpensive, easy to repair, and under normal conditions can last for many years.

Stainless Steel is more expensive, but much stronger and durable than aluminum.
Q:
 		 How can I be sure my motor is operating within the recommended rpm range?
A: This can only be checked with a tachometer. There are various kinds commercially available.
Q:
 		 Will a different prop correct bad torque action (listing and hard steering)?
 
A: Usually not. Most likely it is the result of any of several irregularities in the hull, the steering hook-up or the engine mounting. Steering wheel must be properly located relative to propeller rotation. If an engine has a right hand rotating propeller, steering wheel should be on the right or starboard side. This side normally would tend to lift as the result of torque action and the driver's weight offsets it. Modern outboards have built-in features in the lower units to compensate for torque. Engine tilt should be such that the prop is horizontal when underway. If it is up or down, the propeller can have a definite pull to one side. See that engine is at exact center of the transom and is setting level. Steering linkage should have enough adequate sized pulleys, properly swiveled and with the right cable tension. Check boat bottom for warping, distortion, which could cause difficulty.
Q:
 		 I have a twin engine outboard. Can I get a propeller of opposite rotation and run one motor in reverse?
 
A: No. This is a frequent question, and we would caution anyone against attempting to run any engine in reverse continuously at high speed. The power units are not made to withstand the reverse thrust and this type of operation can only result in lower unit failures. Some lower units have been available with reversed gearing so counter rotating propellers can be used in a dual installation.
Q:
 		 What is the correct transom height for my outboard engine?
 
A: On average boats, it is best to mount the engine so the cavitation plate is approximately 1" below the bottom of the keel, or 1" below the bottom of boats without keel.

For racing boats, better speeds can be attained by raising the engine to reduce lower unit drag and exhaust back pressure. Best transom height can only be determined by experimenting . . . get the engine as high as possible, or to the point just before propeller cavitates excessively.
Q:
 		 What is the best tilt-setting or shaft angle?
 
A: Proper tilt is extremely important, and is determined only through experimenting. In any boat, the tilt-setting can change as the load changes. Tilt adjustment determines the planing angle and if improperly set, the speed loss can be substantial or the boat may not plane at all. Tilting the engine in toward the transom pulls the bow down. Tilting it away from the transom pulls the bow up. Vary the anle to find the point where the boat assumes the best planing position.
Q:
 		 Is it advisable to have outboard props repaired?
 
A: Depends on the material. Those made of sand-cast aluminum are repairable at about 1/3 to 1/2 the new propeller price. Die-Cast propellers generally are not repairable. The material is very brittle, breaks off easily in the straightening process and will not weld satisfactorily. (Original equipment propellers are usually made of die-cast). It is advisable to discard such propellers and replace with the more durable sand-cast aluminum.
Q:
 		 Can I troll better with a different sized wheel?
 
A: Low pitched propellers are always best for trolling. The lower the pitch, the better. Standard propellers with relatively high pitch troll too fast and in throttling down to extremely slow speed, they tend to overload permitting the engine to idle faster while moving boat slowly.
Q:
 		 Can a prop change help me in water skiing?
 
A: Yes, in most cases. Original equipment propellers are pitched a little on the high side. Not knowing the boat the engine will be used with, the manufacturer pitches the prop a little high so the engine does not exceed top rpm if placed on a light boat. However, on a heavier boat, or with water skiers, this propeller tends to overload the engine, resulting in poor speed, poor acceleration and sluggish performance, making it difficult to get a skier up. This is corrected with a lower pitched prop.


 
Q:
 		 Why change propellers?
 
A: The stock propeller with which most outboards are equipped is a compromise. Since it has fixed diameter and pitch, it is really limited in its use and it does not provide satisfactory performance for all the combinations of hulls and loads that will be encountered once it is installed. One important fact to note is that the propeller moves the boat through the water at a specific engine rpm, and h.p. is directly related to the developed rpm. The engine cover is marked with a certain h.p. rating but in most instances the full benefit of the possible h.p. is never realized. Along with the h.p. rating equal emphasis should be placed on the rpm at which the rated h.p. is developed. This, of course, is where the propeller comes into the picture. Outboard engines are designed to be run at peak rpm for full efficiency. Excessive rpm with its increased friction and wear is obviously harmful. It is equally harmful to run the engine so overloaded that it cannot achieve its rated rpm since this results in excessive carbon buildup in the cylinder with subsequent problems of poor fuel economy, pre-ignition, frequent spark plug failure, scoring of the cylinder walls and even burned pistons.