Useful Tips

Pick up screw for - outboard - motor

Outboard motors
135 - 300 h.p.

Stationary engines
MerCruiser with corner
Alpha I / Bravo I

Mercury ScrewsSolas ScrewsBaekSan ScrewsMichigan screws
Screw Details● United States● Production Taiwan● Production Korea● US production
● High quality● Good quality● Acceptable quality● Great quality
● Sleeve included● Average prices● Low prices● Prices are above average
● In stock● In stock● In stock● In stock
● 3, 4 or 5 blades● Aluminum and steel● Only aluminum● Aluminum and steel
Mercury Motors
2.5 - 3.5 hpPlastic / AluminumPlastic
4 - 6 h.p.AluminumAluminumAluminum
8 - 9.9 hp (4-beat.)AluminumAluminumAluminum
6 - 15 h.p. (2-beat.)AluminumAluminumAluminumAluminum
9.9 - 20 h.p. (4-beat.)AluminumAluminum / Steel
20 - 25 h.p. (2-beat.)AluminumAluminum / Steel
Steel
25 - 30 h.p. (2-beat.)Aluminum, 3 lop.Aluminum, 3 lop.Aluminum, 3 lop.
Aluminum, 4 lop.
Steel
25 - 30 h.p. (4-beat.)Aluminum, 3 lop.Aluminum, 3 lop.Aluminum, 3 lop.Aluminum / Steel
Aluminum, 4 lop.Aluminum, 4 lop.
Steel, 3 lop. Steel, 3 lop.
40 - 60 h.p.Aluminum, 3 lop.Aluminum, 3 lop.Aluminum, 3 lop.Aluminum / Steel
Aluminum, 4 lop.Aluminum, 4 lop.
Steel, 3 lop.Steel, 3 lop.
60 - 125 h.p.Aluminum, 3 lop.Aluminum, 3 lop.Aluminum, 3 lop.Aluminum, 3 lop.
Aluminum, 4 lop.Aluminum, 4 lop.Steel, 3 lop. (Apollo)
Steel, 3 lop. (Vengeance)Steel, 3 lop.Steel, 3 lop. (Ballistic)
Steel, 3 lop. (Laser II)
Steel, 4 lop. (Trophy +)
Aluminum, 3 lop.Aluminum, 3 lop.Aluminum, 3 lop.Aluminum, 3 and 4 lop.
Aluminum, 4 lop.Aluminum, 4 lop.Steel (Apollo)
Steel, 3 lop. (Vengeance)Steel, 3 lop.Steel (Ballistic)
Steel, 3 lop. (Laser II)
Steel, 3 lop. (Enertia)
Steel, 3 lop. (Fury)
Steel, 3 lop. (Mirage +)
Steel, 3 lop. (Tempest +)
Steel, 4 lop. (Trophy +)
Steel, 4 lop. (Vensura)
Steel, 4 lop. (Revolution)
Steel, 4 lop. (Bravo I)
Steel, 5 lop. (HighFive)
Stationary MerCruiser engines
With Bravo II speakerAluminum / Steel
With Bravo III speakerSteel

Propeller Selection Chart for Motors Yamaha you can see here.

Propeller Selection Chart for Motors Honda you can see here.

Propeller Selection Chart for Motors Suzuki you can see here.

Propeller Selection Chart for Motors Tohatsu you can see here.

Propeller Selection Chart for Motors Jonhson / evinrude you can see here.

Manufacturers (original and non-original screws)

Here the formula is simple “Original screw = price”, i.e., the price of the original is more expensive.
All motor manufacturers are engaged in the production of propellers. But here Honda until recently, the company put screws on its motors Michigan, and now it’s Solas. And the company Tohatsu puts screws on some of its outboard motors Solas. All manufacturers of outboard motors recommend installing original propellers on their motors.
There are many screw manufacturers on the Russian market, but the most common are Solas and Michigan.

Company Michigan has been producing screws for over 100 years. And it is the largest and one of the most reputable manufacturers. They are mainly engaged in the production of exact copies of the original propellers of all engine manufacturers. But they have their own developments, which, one way or another, improve the characteristics of the motor.

Company Solas makes propellers that can be adapted to any motors. The desire to reduce the cost of production. All screws Solas - This is their own development. We would call Solas - universal propellers for outboard motors.

Types (varieties) and material of screws

A variety of brands, models and power of outboard motors requires a huge number of propellers. They (varieties) are different:

  • step (the distance that the screw travels in one revolution without taking into account slip),
  • diameter (a circle described by the points of the blades farthest from the center),
  • number of blades (usually 3, less often 4 or 2),
  • material (carbon and stainless steel, aluminum alloy, plastic),
  • hub design (rubber damper, replaceable sleeve, replaceable blades),
  • hub design (exhaust through the hub or under the anti-cavitation plate),
  • hub diameter
  • the number of splines of the sleeve.

Marking

Usually applied to the hub or blades, inch sizes are used. If only the catalog number is applied to the screw, for example, 4232-100-18, then the decoding is written on the package. Not all motors have screws as standard. Suzuki has everything but the most powerful. Tohatsu has it. Yamaha has everything but the most powerful. Mercury and Honda have up to 40-50 forces for everything, then they are not included in the package.

11¼ × 15-G - this marking is applied to your Yamaha propeller. The first number indicates the diameter of the blades, the second number is the pitch of the screw. Some manufacturers add to the marking the number of blades and the direction of rotation of the screw, for example: 13 × 19 3RH, or 3 × 10–3 / 8 × 11 R, where the number “3” is the number of blades, RH or R is the right rotation.

We will try to explain it all in a simple way so that you understand.

The first and easiest way to select a screw is to compare two, three, or four screws with different pitch and diameter. By alternately installing them on the same engine (while the engine should run at about 5000 rpm with the throttle fully open), determining which propeller will be more effective when the ship is heavily loaded and which will provide high speed. This method is great, but there is one BUT where to get so many screws for testing. Screw sellers will not give them just like that.

For the second method you need: a boat (boat), a boat motor with a propeller, and a tachometer.
It is necessary to determine the basic parameters of the propeller for the outboard motor. They are the diameter of the screw itself and its pitch. Given these engine power, the maximum speed of the boat depends on these parameters. The distance in inches covered by the propeller in one revolution is the pitch of the outboard motor propeller, it will be the main one. After you pass the run-in, you need to give full throttle and see the tachometer readings. Look in the instructions for the outboard motor (they are indicated there exactly), what maximum speed it can develop at “full throttle”, with the throttle open.
Turnover for Suzuki PML - max 6000–6300.
For Tohatsu, Mercury, Yamaha, Honda - max 5000–5500.
And now we look, does not spin or twist your motor.
Next, by choosing the pitch or diameter, we select the suitable screw.

Do not twist - we reduce the pitch of the screw.
Twists - we add a pitch of the screw.
Screw pitch - 200 revolutions.
Diameter 1 inch - 500 rpm.
Diameter 0.5 inches - 250 rpm.

Remember: when choosing a screw for the PLM, follow a certain rule. Use large pitch propellers for high-speed light boats, and smaller pitch propellers for slow and heavy ones. Changing the propeller pitch of an outboard motor is the only way to align the propeller with the engine and with the boat.

Aluminum screws are ideal for those who count their money, maximum speed is less important than the economical (cruising) speed, at which both materials behave approximately the same.

Polished stainless steel screws are the best choice when strength and efficiency are essential. Since steel screws are seven times stronger than aluminum, manufacturers can make screws significantly thinner without compromising their strength and stiffness.

If the motor reaches maximum speed at full throttle and during normal loading, then the screw is most likely selected correctly.

Do not allow continuous operation of your motor at revolutions that exceed the recommended ones. This may cause damage to the outboard motor.

Yours sincerely,
collective "Sea of ​​boats"

Main propeller specifications

Currently, propellers of various designs are being manufactured, depending on the conditions in which it will be used, you can choose the screw most suitable for you.

What you need to pay attention to:

  • screw diameter is the distance from the center of the sleeve to the edge of the blade times 2,
  • propeller pitch is the distance that the propeller per revolution, it depends on the angle of inclination of the blades. The greater the angle of inclination, the greater the step,
  • the shape and direction of the propeller blades.

The main characteristic that you need to pay attention to when choosing a screw is the ratio of screw pitch to diameter. They recommend following the principle - the faster the boat, the greater the step ratio.

If you have a light high-speed boat, then you need to choose a screw with a step ratio greater than one. For fast boats, a step ratio of 1.2 is recommended. For simple boats this ratio should be equal to 1, and for heavy low-speed boats intended for the carriage of goods, this ratio should be about 0.8.

What shape of the blade to choose

Propellers produce various shapes. Each is for specific purposes.

Consider the main types of blades:

  • zero stroke blades such blades are perpendicular to the hub, they differ in that they contribute to the maximum lifting of the bow of the boat and contribute to gliding,
  • blades twisted in the direction of rotation of the screw, differ in that during rotation they cut any grass, and the algae that get on the screw and prevent them from twisting are ideal for swimming in overgrown ponds,
  • elliptical blades give the ideal ratio of traction and speed,
  • pointed tips put on high-speed boats, since friction when using them is minimal.

How many blades to choose

When choosing propellers, there are certain recommendations that up to the number of blades - the more blades, the less vibration from engine operation, but friction increases, since the contact area of ​​the screw with water increases, so the power drops, although slightly.

True, there is another plus - fuel consumption decreases with increasing number of blades. And many only because of this try to put screws with four blades.

Which screw is suitable for the motor

Despite the huge number of propellers, in the end it is necessary to choose the most suitable screw for a particular motor. How to choose this one and only screw? A lot comes with time, as a result of trial and error.

  • Some believe that the manufacturer himself installs the most optimal screw on this motor, which is naturally a delusion, because the manufacturer does not know in what specific conditions you will use your craft. But, in order not to choose a blind screw, you need to use one rule when choosing a propeller.
  • After you determine the shape of the screw and the number of blades, you should pay attention to such a characteristic of the propeller as the dependence of its power on the number of revolutions - this is a parabolic graph and compare it with the graph of the dependence of engine power depending on engine speed - this is also a curve.
  • TThe screw schedule, whose power will go through the highest point in the engine power chart, will ideally fit. If this intersection point is to the left of this peak, then your screw will not use all the engine power, if to the right, then to achieve maximum speed, the engine must run at speeds exceeding the normal engine operation, which will lead to rapid wear of the piston system parts.

Propeller Tips

Recently, propellers made of composite materials, the so-called plastic propellers, have begun to enter the Russian market.

They have one feature:

  • Price. Yes they are really cheap.

But they have a lot of disadvantages:

  • Firstly, they are absolutely non-repairable, if something happened to him it cannot be welded, screwed, bent, you can only throw it away.
  • In addition, from the thick profile in the manufacture it has a very large surface area, which increases the friction force and leads to an excessive consumption of fuel, so over time the amount spent on excess fuel will far exceed the money that you saved when buying a screw. Buying such a screw is not recommended.

Tips:

  • If your motor develops less than the speed indicated in the passport, then it is necessary to reduce the pitch of the screw. Reducing the pitch of the screw by 2.5 cm or 1 inch will increase the speed by approximately 200. Well, accordingly, if your motor develops high speed, then do the opposite - increase the pitch.
  • To reduce the speed of exit to gliding, it is necessary to choose screws with a large step ratio or increase the diameter of the screw. True, there is no need to overdo it. If the diameter is too large, this will lead to damage to the gearbox. For example: a four-blade propeller Solas.
  • To increase the speed, take a stainless steel screw, and ideally it should be a ventilated polished screw.
  • Try to choose a screw of the same manufacturer as the manufacturer of your motor. Since companies often develop screws with the most suitable parameters for their engines.

Propellers for Suzuki motors

For Suzuki brand motors, it is necessary to choose propellers so that when they are installed, the engine speed at full speed would be from 5200 to 5700 rpm. For light boats, propellers with a stroke diameter of 11 inches to 17 inches are suitable, for medium 11.5 inches to 13 inches or 11.5 to 11 inches. For heavy boats carrying cargo, grab a propeller with a stroke diameter of 11.5 inches to 9 inches.

Propellers for Tohatsu motors

For Tohatsu brand motors, propellers must be selected so that the engine rpm at full throttle is in the range of 4500-5500 rpm. For different types of boats you need different in size ratios stroke propellers. For light boats, propellers with a ratio of 7.9 inches to 9.0 inches are optimal. Propellers with a ratio of 7.9 inches to 7.9 inches are suitable for medium boats. And on heavy boats it is better to install propellers with a ratio of 7.9 inches to 7.0 inches.

Propellers for Mercury motors

When selecting a propeller for a mercury motor, it must be borne in mind that the maximum engine speed must be between 4500-5500 rpm. The diameter of the propeller for the Mercury engine varies from 12 to 14 inches. The lighter your boat, the smaller the diameter is more appropriate to choose. The propeller pitch for Mercury motors varies from 10 to 23 inches. When choosing a propeller, the rule must be observed, the heavier the boat, the smaller the pitch you must choose.

Outboard Propeller Protection

It should be noted that at maximum speeds, no protection will save your screw if it bumps into stones, snags on the bottom or any other obstacle, in addition, any protection reduces the power of the screw.

To protect the screw, you can use a casing, which is made of steel and attached to the anti-cavitation plate. When installing the protection, it is necessary to ensure that the distance between the casing and the screw is minimal.

You can also protect the screw by installing a shock absorber made of metal rods on the gearbox that bends around the screw on all sides. You can attach a pin to the gearbox, which will lower below the screw, and signal when approaching a dangerous shallow water.

Screw repair

The main breakdowns of the propeller are the bends of the blades, cracks in the blades or their breaking off:

  • Bends of brass screws up to 30 degrees can be aligned to cold. To do this, it is necessary to use rods about a meter long, with slots at the edges 6-8 cm deep. If the bends are more than 30 degrees, then the blade must be heated to a temperature of 600-700 degrees, it is better to warm up in a kiln, as it provides the most optimal heating the entire surface.
  • After editing, it is necessary to anneal the screw to relieve tension. To do this, first slowly heat the screw not more than 100 degrees per hour to a temperature of 450-500 degrees, and then slowly cool it at a speed of no more than 50 degrees per hour. For welding brass parts, it is necessary to use argon-arc welding.
  • When bending steel screws, annealing is not used to relieve stress.
  • After applying welding, it is necessary to eliminate the influx by treating the seam with a file or sandpaper.
  • At the end of the repair, it is necessary to balance the weight of each blade, this is done by cutting off excess weight over the entire area of ​​the blade. To determine which blade is heavier, it is necessary to put a screw on the sleeve and the heavier blade will lower.

Using this manual, you can easily select the propeller you need for yourself and enjoy riding on your boat.