Speed of the outboard motor 5 hp: real numbers, calculations and secrets of acceleration

Choose a outboard motor with power 5 hp And you want to know how fast it can go on your boat, and that's a question that's a concern for beginners and experienced water-engineers alike, because speed is not just about comfort, but also about safety, fuel consumption, and sometimes legality of operation (in some regions, power restrictions are in place). real-time motor-driven Yamaha, Mercury, Tohatsu, HDX and other brands tested on PVC, aluminum and inflatable boats with a hard bottom.

Let's warn you right away. There is no universal answer to the question “What is the speed of 5 hp?”, because the final result is influenced by at least 7 factors. - from the weight of the boat and passengers to the shape of the hull and the condition of the propeller. Mercury ME F 5 M lightboat Flagship 320 show 25-28 km/hAnd on a loaded aluminum Kazanka, it barely squeezes. 15–18 km/hWe've gathered data from real-world tests, powerboating forums and technical specifications so you don't have to guess.

In the article you will find:

• 📊 Speed table for popular boats and motors 5 hp
• 🔧 Factors that are slowing down your motor (and how to eliminate them)
• ⚡ Ways to increase speed without buying a new engine
• ⚖️ Legal nuances 5 hp engines in Russia and CIS

1. Real engine speed 5 hp: test data

To avoid using bare numbers, we analyzed the results of tests conducted by boat owners on the forums. ForumHouse, BoatPlace And in YouTube reviews, it's important that all measurements are taken with calm-water, without current or wind, with one passenger (weight ~80 kg). AI-92, screw - standard aluminum (step) 7-9 inches).

Motor model	Boat type (length, m)	Max. speed, km/h	Acceleration time to 20 km / h, sec	Fuel consumption, l/h
Yamaha FMHS 5	PVC Flagship 320 (3.2 m)	26–28	12–14	1.8–2.1
Mercury ME F 5 M	aluminum Kazanka-M (3.6 m)	18–20	18–20	2.0–2.3
Tohatsu MFS 5	Inflatable Zodiac Cadet 285 (2.85 m)	24–26	10–12	1.6–1.9
HDX T 5	PVC Flying wing 330 (3.3 m)	22–24	15–17	1.9–2.2
Suzuki DF5AS	aluminum Dive 360 (3.6 m)	20–22	16–18	2.0–2.4

As you can see from the table, the speed range reaches 10 km/h - It's almost 40% difference It's between the fastest and the slowest combination. hydrodynamics of the boat hull: flat-bottomed aluminum models create greater water resistance than PVC boats with keeled cylinders. construction: for example, Zodiac Cadet 285 weight 32 kgeh Kazanka-M — 80 kg.

2. What does the speed of the 5 hp engine depend on?

If you expect from your motor 25+ km/hbut in practice you get it. 15–18 km/hThe problem is that we've got one or more of these things down below, and we've put them down by their degree of influence, from the most critical to the secondary.

• ⚓ Boat weight + passengers + cargoEvery additional 50 kg slow down 1-2 km/hFor example, if you bring a battery with you. 18 kg, tackle box 10 kg and the second passenger 80 kgThe total overload will be 108 kg - It's a minus. 2-3 km/h to maximum speed.
• 🌊 Boat hull shapeFlat-bottomed aluminium boats (Kazanka, Dive) always slower than keeled PVC (Flagship, Winger.) due to increased water resistance. The difference can be as high as 5-7 km/h All other things being equal.
• 🌀 Condition and type of propellerStandard aluminum propeller with pitch 7-9 inches It is optimal for most cases, but if it is bent or has chipped, the speed drops by a small amount. 10–15%Smaller pitch steel screws (STEAM)5-6 inches) give better acceleration, but reduce the maximum speed.
• 🛢️ Fuel quality and oilUse. AI-95 instead AI-92 add 0.5–1 km/hBut only if the engine is designed for high-octane fuel, poor quality oil (or its absence in two-stroke engines) leads to a loss of power to the maximum of the engine. 20%.
• 🌬️ External conditions: wind, current, waves, in the headwind 3-4 m/s speed 3-5 km/hAnd, if it is, it may increase temporarily. 1-2 km/h.

3. How to increase the speed of the engine 5 hp without tuning?

If your engine doesn't pull, don't rush to spend money on a more powerful model. In most cases, you can increase the speed by a higher speed. 10–20% No big investment. 5 Proven MethodsThe results are obtained after the first launching:

• 🔄 Replace the propellerIf you have a standard aluminum screw with pitch 7 inchesTry steel with step. 8-9 inches (for example, Michigan Wheel Apollo or Solas AmitaThat might add to that. 2–4 km/hBut it requires testing - on overloaded boats, the engine may not "pulle" a big step.
• ⚖️ Reduce the weight of the boatTake away the unneeded load: the extra crates, the heavy batteries (replace with lithium), the old oars. Every one saved. 10 kg add to 0.2–0.3 km/h.
• 🛠️ Adjust the angle of inclination of the motor (trim)The best angle for most boats is 2-3 holes If the bow of the boat is too uptight, increase the angle; if it is "blown" - reduce.
• 🧴 Use quality oilFor two-stroke engines, choose oil with the label TC-W3 (for example, Motul Outboard Tech 2T or Liqui Moly Marine Outboard 2TIt'll reduce friction and add to it. 0.5–1 km/h.
• 🧼 Clean the boat hull and propellerAlgae, seashells or even a thin layer of dirt on the bottom of the boat increase the resistance to the water. 5–10%Same goes for the screw -- check it for growths.

Remove extra cargo from the boat

Check the pressure in cylinders (for PVC)

Clean the screw from algae and dirt

Refuel with high-quality fuel (AI-92/AI-95)

Adjust the angle of the motor's inclination--

One of the most effective ways is to screw-upLike the motor. Tohatsu MFS 5 standard-rotor 7×7 (diameter x step) gives 22 km/hand the screw Solas Amita 3x9x11 (step) 11 inches) accelerates the same boat to 26 km/hBut be careful: too much can lead to motor-loading and overheating him.

What happens if you put a screw with too much stride?

If the pitch of the screw exceeds the recommended for your motor, the engine will not be able to develop sufficient speeds (less than the speed limit). 4500-5000 rpm This results in:

• 🔥 Overheating of the engine due to increased load
• 🐢 A sharp drop in speed (the engine "choked")
• ⚠️ Risk of damage to the piston group during prolonged work

The optimal step is selected experimentally: the motor should go to the 5000-5500 rpm Full load.

4. Legal restrictions for 5 hp motors

In Russia and CIS countries, engines with power up to 5 hp (3.68 kW) category “Small-sized courts without the right of registration”That means you don't need to:

• 📄 Make out boat-certificate GIMS.
• 💳 Pay. state duty For registration.
• 👮 Walk through technical inspection.

But there are important nuances:

1. If you install the motor 5 hp on a boat longer than 2.5 mIn some regions (for example, Moscow, St. Petersburg) it may be necessary to boat-board As a small boat, even if the engine is less than 5 hp.
2. In the waters with power-limitation (e.g. conservation areas) 5 hp motor may be banned. 3.5-4 hp.
3. For motorboat control 5 hp GIMS license are not requiredbut if the power is greater than 5 hp (Even 0.1 hp), you need to take the exam.

⚠️ Attention! In Belarus and Kazakhstan, the rules are stricter: motors from the 3.7 hp The threshold is registered in Ukraine. 5 hpBut from 2023, tightening to 3.5 hp.

5. Test drive: how to measure the speed correctly?

Many owners of 5 hp engines mistakenly measure the speed of the engine. GPS-navigator Or a smartphone, without regard to external factors. precisenessFollow this instruction:

1. Select the terms:
   • Calm water (excitement no more) 1 point).
   • No wind (or minimum side wind) 2 m/s).
   • Depth not less 1.5 m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m (So that the screw does not pick up the silt from the bottom).
2. Prepare the boat:
   • One passenger (weight ~80 kg).
   • Full tank of fuel (but no additional canisters).
   • Clean screw and body.

Take measurements:

• Accelerate the boat to maximum distance 200-300 m.
• Record the speed by GPS (use the apps) Speedometer or GPS Status).
• Repeat 3 times and take the average.

Typical errors in measurements:

• 🚫 Measurement of speed immediately after the start (the engine did not reach maximum speed).
• 🚫 Use of the speedometer of the boat (accuracy to the 10–15%).
• 🚫 Testing in a headwind or current.

💡

For the most accurate measurements, use two GPS devices Simultaneously (e.g. smartphone + navigator) if readings differ more than 1 km/hRepeat the test.

6. Motor 5 hp vs 9.9 hp: is it worth overpaying?

Many boat owners are not sure whether to buy a motor. 5 hp fork out 9.9 hpThe difference in price between new models. 50-70 thousand rublesBut is it justified? Let's compare it in key terms:

Parameter	5 hp engine.	Engine 9.9 hp.
Max. speed (boat 3.3 m, 1 passenger)	22-26 km/h	35-40 km/h
Fuel consumption, l/h	1.8–2.2	3.5–4.5
Motor weight, kg	22–26	35–45
Registration with GIMS	Not required	Required (GIMS license)
The cost of a new, thousand rubles.	80–120	180–250

Conclusions:

• ✅ 5bhp is optimalIf you:
  • Catch fish in small water bodies.
  • Carry the cargo before 200 kg.
  • You want to save on fuel and registration.
• ❌ 9.9bhp is needed.If you:
  • Walk on large rivers or sea (you need a power reserve for the wave).
  • Carry 3+ passengers or heavy equipment.
  • We are willing to spend more on fuel and paperwork.

⚠️ Attention! Motors. 9.9 hp It is often sold in a "short-down" version before 5 hp These models can be legally used without registration, but after the restriction is removed, you will need to register with the GIMS.

7. Maintenance of the engine 5 hp: how not to lose speed?

Even the most reliable engine. Yamaha or Mercury And you lose power over time if you neglect maintenance. focal pointwhich affect the speed of:

• ⚙️ Ignition candleReplace her after. 100 motor-hours or if:
  • The engine doesn't start well.
  • The vortex floats idling.
  • Speed's down. 3+ km/h No apparent reason.

  Recommended candles: NGK BP6HS or Champion L78YC.

• 🛢️ Fuel systemOnce a season, flush the carburetor (for two-stroke engines) or check the pressure in the fuel pump (for four-stroke ones). A clogged chickle can slow down the speed by a few minutes. 5-8 km/h.
• 🌀 The propeller shaft and the propellerCheck for:
  • The bent blades of the screw.
  • Corrosion on the shaft.
  • Luft in bearings.

  Even a little backlash (1-2 mm) takes away 1-2 km/h.

• 🧴 Oil in the gearboxChange every one. 50 hours of motorsport Or before you can save it in the winter. SAE 80W-90 (for example, Motul Gear 300).

If the engine is "dumb", check:

1. Status. air-filter (clogged - speed drops) 2-3 km/h).
2. Level. compression cylinder (normally-- 8-10 atm).
3. Integrity fuel-hose (Cracks lead to air suction).

FAQ: Frequent questions about 5 hp engines

🔹 Can I put a 5 hp engine on a boat 4 meters long?

Yes, but the speed will be low - no more. 15–18 km/h Because of the weight and the resistance, the optimal length of the boat for 5 hp. 2.8–3.6 mFor a 4-meter boat, it is better to consider the engine 8-10 hp..

🔹 Which screw is better for the Tohatsu 5 hp engine - aluminum or steel?

The steel screw is stronger and more accurately balanced, which gives an increase in the 1-2 km/hBut it's more expensive, and it can damage the gearbox when it hits an obstacle. Aluminum screw is cheaper and safer for the engine. Aluminum is recommended for beginners, incremental steel for the experienced. 8-9 inches.

🔹 How much fuel does the engine consume 5 hp per hour?

The consumption depends on the load:

• Idle: 0.5-0.7 l/h.
• At cruising speed (15–20 km/h): 1.2–1.8 l/h.
• At maximum speed: 2.0–2.5 l/h.

There's enough for a 5-liter canister. 2-4 hours active use.

🔹 Should I register a 5 hp boat in 2026?

In most regions of Russia, noif the length of the boat is up to 2.5 m m m mFor boats longer. 2.5 m m m m The rules vary:

• Moscow, St. Petersburg: Registration is mandatory.
• Regions: Not usually required, but check with your local GIMS.

In Belarus and Kazakhstan, motors from 3.7 hp are subject to registration.

🔹 Why does my 5 hp engine not develop more than 15 km / h?

The reasons may be as follows (in decreasing probability):

1. Boat overload: weight > 300 kg).
2. The wrong screw is chosen (too big step).
3. The carburetor or fuel filter is clogged.
4. Worn candles or low compression.
5. The angle of the motor is not adjusted.

Start with a check. weight and screw - That solves the problem in 70% of cases.