Choosing an outboard motor for a boat is always a compromise between the speed, the payload and the budget. 20 hp outboard motor. It occupies a unique niche, as the boundary value where the low-power class ends and a full-fledged middle class begins. For many owners of PVC inflatable boats, from 3.2 to 3.9 meters in length, as well as small metal "Kazak", this power becomes the "golden mean".
Why twenty forces? This is the threshold that allows you to confidently bring the boat to plane even with two passengers and a minimum load, but it does not require complicated registration with the GIMS in some cases (if the total power of all engines does not exceed the threshold values relevant to a particular region and type of boat). 20 hp outboard motor. It is no longer a toy for quiet movement, but a serious tool for fishing, hunting or family recreation on the water.
In this article, we will analyze in detail the technical nuances, compare two-stroke and four-stroke units, and also consider the features of operation of such engines. You will learn what to look for when buying used equipment and how to extend the life of a new device, avoiding typical mistakes of beginners.
Two-stroke or four-stroke: the eternal argument in the 20 hp class
When buying a 20 horsepower engine, the owner inevitably faces the dilemma of choosing a cycle of work. Two-stroke engines (2T) is traditionally cheaper, easier and easier to transport, they are not afraid of tilting during the course, which is critical for some types of boats, but their appetite for fuel and oil is much higher, and noise and vibration levels can be tiring during long transitions.
On the other hand, four-stroke (4Ts) offer a whole different level of comfort: they're quieter, more economical and more environmentally friendly. But here's the caveat: a four-stroke of this power will be noticeably heavier than its two-stroke counterpart. If every extra kilogram on a transom is critical for your boat, that can be a deciding factor.
- 🚀 Dynamics: Two-strokes are usually faster gaining momentum, providing a quick exit to plane.
- ⛽ Economics: Four-strokes consume 30-40% less gasoline and do not require mixing oil with fuel.
- ⚖️ Weight: The 2T engine weighs an average of 35-40 kg, while the 4T can reach 50-55 kg or more.
- 🔧 Maintenance: 4T requires regular oil change in the crankcase, 2T - only mixtures in the tank.
⚠️ Warning: When choosing a two-stroke engine, strictly observe the ratio of mixing oil and gasoline specified in the instructions. Using old oil or the wrong dosage is guaranteed to lead to a bully of the piston group.
And you also have to consider that today's four-stroke technology has come a long way. Many models now have electronic throttle controls, which makes them even smoother. If you plan to use the boat primarily for trolling or quiet fishing, where low flow and silence are important, the 4T will be the leader.
Technical specifications and productivity
Considering 20 hp outboard motor.It's not easy to ignore its traction specifications. Usually, these units are equipped with screws with pitch that ensure optimal operation in the range of 4500-5500 rpm. It is important to understand that the declared power is achieved only at full speed. At low speeds, when trolling, the difference between 2T and 4T becomes even more noticeable in favor of four-strokes.
The cooling system in most models in this class is forced, water, which means that the water is drawn through the intake in the lower unit. Critically important Never run the motor out of water without a special nozzle or capacity, as the rubber impeller pump burns in seconds.
The table below compares the averaged specifications of the two popular models:
| Parameter | two-stroke (20 hp) | four-stroke (20bhp) | Units |
|---|---|---|---|
| Weight. | 36 - 42 | 48 - 56 | kilogram |
| Fuel consumption (max) | 6.5 - 7.5 | 4.0 - 5.0 | l-hour |
| Workload | 330 - 360 | 360 - 400 | cm3 |
| Noise level | Highly | Low/Mediocre | dB |
The ignition system deserves special attention. Yamaha, Tohatsu or MercuryIt uses electronic ignition (CDI or TCI), which does not require adjustment of the gaps, unlike older contact systems, and this improves the reliability of the launch in wet weather.
Compatibility with PVC and aluminum boats
The 20 hp engine is the most recommended for many inflatable boats with a length of 3.2-3.6 meters. Installing a more powerful unit on a light PVC boat can lead to yaw, “cobra” at full speed and rapid wear of the transom. For aluminum boats (for example, “Kazanka-M” or “Winds” modifications), this power is also a comfortable maximum for single or pair fishing.
When you're putting a PVC boat, it's important to consider the length of the lower unit. S (Short) - 381 mm or L (Long) Inflatable boats are most commonly used for short-dadewood, if the anti-cavitation plate is too high, cavitation and loss of traction will occur; if it is too low, water resistance will increase.
When you install the engine on PVC boat, use transom wheels. The 20 hp engine weighs a lot with lower unit, and dragging it by hand across the beach or reeds is questionable pleasure.
For flat-bottomed metal boats, 20 forces may not be enough to go to the plane with a full load, but for keel aluminum boats up to 4 meters long, this option is optimal. It provides speeds of about 30-35 km / h, which is enough to move around large reservoirs.
Fuel consumption and economic efficiency
The question of how much the engine eats worries each owner. For a two-stroke engine of 20 hp, the average flow rate at full gas is about 7 liters per hour. At a cruising speed (about 3000-3500 rpm), it decreases to 3-4 liters. Four-stroke analog will show figures of about 4.5-5 liters at full gas and 2-2.5 liters in economical mode.
However, the savings are not only from gasoline. Two-stroke engines The ratio is usually 1:50 (50 liters of gasoline 1 liter of oil) or 1:100 for modern synthetics, which is an additional cost that must be considered when calculating the cost of a motor watch.
If you count on money, during the active season (about 100 motor hours), the four-stroke engine will pay off its higher initial cost by saving on fuel and not having to buy oil for the mixture.
Maintenance and preparation for winter storage
Anyone. 20 hp outboard motor. Basic maintenance includes changing the oil in the gearbox (usually once a season or every 100 motor hours), lubricating the syringes and checking the spark plug. In four-strokes, the engine oil and filter are also changed.
☑️ Checklist for winter preparations
Pay special attention to the cooling system. After each trip, especially in shallow water or in overgrown places, you need to visually inspect the control hole for the water jet, if the jet is weak, perhaps clogged water intakes or worn out impeller pump.
⚠️ Warning: Never keep the motor upright if there is oil left in the carburetor or 4T lubrication system, unless the instructions allow it, it is best to use a special stand or transport box that locks the engine in the working or slightly inclined position.
Preservation for the winter is mandatory. Gasoline is oxidized during the season and converted into resins that clog the carburetor's jellyplants. Either drain the fuel completely and start the engine until residue is produced, or use special residues. fuel stabilizerThey allow you to store gasoline in the tank until the next season without losing properties.
Overview of popular models and brands
The 20 hp motor market is represented by both eminent Japanese brands and affordable Chinese counterparts. Tohatsu M20C2S It's a lightweight, simple and unkillable unit that's often put on fishing boats.
In the four-stroke segment stands out Yamaha F20It's heavier, but it offers incredible smoothness and low vibrations. MercuryThey're often technical twins of Tohatsu, but in a different husk. Hidea and ParsunThose who have been in the service for years.
The secret of choosing a used motor
When buying a motor from hand, be sure to ask the seller to start it. Pay attention to the color of the exhaust: bluish smoke is normal for 2T, but black or blue thick smoke indicates problems with the fuel mixture or oil removable rings (in 4T). Also listen to work on idles - there should be no dips and knocks.
When choosing between a new "Chinese" and a used "Japanese" ten years ago, a new engine often wins with a guarantee, if you are not an expert in the repair of the internal combustion engine. Modern Chinese factories produce products of quite decent quality, using licensed drawings.
The main criterion for choosing a 20 hp engine is not only the price, but also the presence of a service center of the chosen brand in your region.
Frequently Asked Questions (FAQ)
Do I need registration in GIMS for a boat with a 20 hp engine?
Under current Russian law, small vessels with an outboard motor of more than 8 kW (roughly equal to 10.88 hp) are subject to registration. must be registered and requires the right to operate a small craft of category "M" (motor boat).
What kind of gasoline to pour into the engine 20 hp?
Most modern engines, especially those with electronic ignition, are designed for gasoline. AI-95Use. AI-92 It's possible, but it can cause detonation and power loss, and it can cause overheating. Tohatsu, Yamaha Or another.
Can I develop full gas when running a new engine?
Absolutely not. The break-in usually lasts 10 hours. In the first hours (up to 2-3 hours), it is recommended to keep the speed up to 50% of the maximum, then gradually increase the load. Working on full gas during the break-in will lead to overheating and piston bullying, since the parts are not yet erased.
Why does the engine stop at high speeds?
The main reasons: the fuel filter clogged, water got into the tank, the ventilation of the tank was disturbed (the hole in the lid was clogged), or the setting of the carburetor was lost.