Choosing a reliable power unit for an inflatable or small-sized metal boat is always a trade-off between power, weight and cost of ownership. In the segment of budget outboard motors, models marked 9.8 horsepower are a special place, since this is the threshold that allows you to operate a boat without the mandatory rights of category “M” in many jurisdictions, although GIMS rules require careful study. Among the many brands that have flooded the market, the model is the model that is the most popular in the world. Kamisu Sea Pro 9.8 2T It is famous for its popularity among fishermen and lovers of active recreation on the water.
The two-stroke design of this engine gives it excellent traction at low rpm, which is critical for planing under full load. two-stroke This allows for higher power density with less weight, making the boat more maneuverable and easier to transport, which is especially true for owners of small cars or those who store equipment in the garage.
However, operation of the motor Kamisu Sea Pro 9.8 It requires strict maintenance, particularly proper preparation of the fuel mixture. Ignoring the proportions of oil and gasoline can lead to catastrophic consequences for the cylinder-piston group. In this article, we will discuss in detail the technical nuances, the process of running and the typical problems that the owner of this popular "nine" may face.
Technical specifications and design features
Engine. Kamisu Sea Pro 9.8 2T It's based on a time-tested architecture that has proven itself in a variety of climates, and it's based on a single-cylinder, forced-air-cooled unit that simplifies the design and reduces weight, and it has a displacement of 169 cubic centimeters, which is the standard value for a class of engines that have a capacity of about 10 horsepower, and it's an electronic ignition system (CDI) that guarantees a stable spark even when idling.
⚠️ Attention: Motor cooling system Kamisu Sea Pro 9.8 It is strictly forbidden to start the engine outside the water or with a blocked water intake, this will lead to instant overheating and deformation of the cylinder head.
An important design element is the lower unit, which is usually 381 mm long (standard S), which is suitable for most PVC and aluminum boats with a transom standard height. The weight of the engine in running order (without fuel) is about 27-28 kilograms. For comparison, four-stroke analogues of similar power can weigh 5-7 kg more. Carburetor system The power in this model requires periodic cleaning, especially if you use gasoline that is stored in the tank for a long time.
The gearbox is equipped with a forward-neutral-back gearshift system, implemented through the thrust of the tuber. The gear ratio of the gearbox is usually 2.08:1, which provides the optimal balance between thrust and maximum speed. The design provides zinc anodes for protection against galvanic corrosion, but their condition must be checked after each release to salt water.
The process of breaking in: a critical stage
New engine break-in Kamisu Sea Pro 9.8 2T It's not just a formality, it's a necessary process of working on rubbing parts. Two-stroke engines are particularly sensitive to the quality of the lubrication in the first hours of operation, because it's during this period that the microrelief on the surfaces of the piston and cylinder is formed, and neglecting this step can reduce the life of the engine by two or more times.
The process of running in three stages, each of which requires a different fuel mix, and unlike four-stroke engines, where oil is poured into the crankcase, the lubrication takes place directly in the combustion chamber, so the quality and quantity of oil in gasoline is crucial.
- 🛑 First stage (0-1 hour): The engine is running at idle or minimum speeds. The mixture is prepared in a ratio of 1:25 (oil: gasoline), during which time it is forbidden to open the throttle by more than 30%.
- 🚤 Second stage (1-5 hours): Short-term load increases to 50-60% of maximum power are allowed. The ratio of the mixture remains 1:25. You need to take breaks every 20-30 minutes to cool down.
- ⚡ Stage Three (5-10 hours): The motor can be glided, but not more than 70-80% of the power, and the mixture gradually changes to the standard 1:50 by the end of this period.
After the first 10 hours of the motor, you need to replace the spark plug, even if it looks normal, and check the tightening of all external bolt joints, as they can weaken from vibration. It is also recommended to drain the residue of fuel from the float chamber of the carburetor if the engine is not planned to be used in the coming weeks.
☑️ Checklist of successful break-in
Fuel system and mixture preparation
Quality of motor operation Kamisu Sea Pro 9.8 2T Two-stroke engines don't have a separate lubrication system, so the oil mixes with the gasoline, and using poor-quality oil or misalignment leads to the formation of soot on the piston, the coking of exhaust windows and, ultimately, to bullies.
It is recommended to use AI-92 or AI-95 gasoline (with an octane number of at least 92). The use of fuel with a lower octane number can cause detonation, which is destructive to the piston group. The oil should be specifically designed for two-stroke engines with air or water cooling and be labeled TC-W3. Mineral oils are cheaper, but synthetic and semi-synthetic provide better protection and less smoke.
| Operational phase | Proportion (Oil: Gasoline) | Oil volume per 10 liters of gasoline | Mode of work |
|---|---|---|---|
| breaking in (0-10 hours) | 1 : 25 | 400ml | Splendid, up to 80% power |
| Standard regimen | 1 : 50 | 200 ml | Full speed range |
| Long-term trolling | 1 : 60 - 1 : 80 | 125-160 ml | Low RPM (< 3000 RPM) |
| Maximum loading | 1 : 40 | 250 ml | Short term, full gas. |
When preparing the mixture, this ensures a more even distribution of lubricating components. The finished mixture is not recommended to be stored for more than 30 days, since gasoline loses its properties and the oil can precipitate.
What happens if you pour less oil?
Reducing the amount of oil in the mixture (e.g. 1:100 instead of 1:50) will lead to oil starvation. The piston will heat up more than the cylinder, expand and jam, resulting in expensive CNG repairs and replacement of crankshaft bearings.
Selection of propeller and speed specifications
Motor. Kamisu Sea Pro 9.8 It is usually equipped with an aluminum propeller, the parameters of which are matched for an average PVC boat with a length of 3-3.5 meters. However, to achieve maximum efficiency, it is important to understand how the diameter and pitch of the propeller affect the behavior of the boat. The screw pitch is the distance that the propeller theoretically travels in one revolution in a solid environment.
If the boat is hard to glid, the engine is not pulling and stalls when you add gas, maybe the pitch of the screw is too big for you to load. In this case, it makes sense to consider installing a screw with a smaller pitch. Conversely, if the engine is easily spinning to maximum speed, but the boat does not develop the expected speed, you need a screw with a larger pitch.
- 🌊 For heavy boats and cargo transportation, a 6-7 inch propeller is recommended, which will provide better traction at launch.
- 🏎️ For high-speed walks light: the optimal step will be 8-9 inches, which will allow you to realize the maximum speed.
- ⚖️ The 7-8 inch step is suitable for most fishing and recreation scenarios.
Maximum speed of motor boat Kamisu Sea Pro 9.8 2T Depending on many factors: hull contours, passenger weight and equipment, bottom condition. On average, a 3.2-meter inflatable boat with one passenger will be able to reach a speed of about 25-28 km / h. Increased propeller pitch can add 2-3 km / h, but only if the engine has a margin in terms of revs.
Adjusting the carburetor and setting up the idle
The carburetor is the heart of the fuel system, and its proper tuning is critical to stable operation. Kamisu Sea Pro 9.8Factory settings may not be ideal for a particular instance of motor or climatic conditions (height above sea level, temperature).
Low Speed regulates low-speed operation, and the number screw (or throttle emphasis) sets minimum idling speeds. High Speed is sometimes found, although it is often locked with a stub in simple models. A tachometer is needed to fine-tune it, because ear tuning often leads to errors.
The sequence of basic settings:1. heat the engine to operating temperature (5-10 minutes).
2. Wrap the screw of the quality of the mixture to the end (without effort!), then turn 1.5-2 turns.
3. The screw of the number to set the turns of idling so that the engine does not deafen.
4. Smoothly wrapping the screw of quality, find a position where the turnover will begin to fall.
5. Turn the quality screw back until the turnover grows to the maximum.
6. Adjust the number of revolutions XX to 900-1000 rpm with a screw.
⚠️ Attention: A poor mixture (low gasoline, lots of air) is more dangerous than a rich one. It causes the engine to overheat. If after setting up the engine stalls when the gas is opened sharply or whistles, immediately stop operating and enrich the mixture by turning the quality screw.
When setting up your carburetor, always have new candles on hand. After each series of adjustment experiments, twist the candle and look at the color of the coar: brick is normal, black is rich, white is poor.
Typical malfunctions and methods of their elimination
Like any other technique, the motor Kamisu Sea Pro 9.8 2T Most of them are related to the fuel system or ignition system and can be eliminated on their own with the basic tools and understanding of the principles of operation of the ICE.
One of the most common problems is difficulty starting. If the engine doesn't start, the first thing you need to do is check for a spark. To do this, twist the candle, put the IB wire tip on it, press the threaded part to the mass of the engine (metal part) and pull the starter. The spark should be bright, blue and stable.
- 🔥 No spark: Check the candle (replace it with one that is known to be working), check the contact of the “mass” (foot button), inspect the ignition coil for cracks.
- 💧 No fuel: Check the fuel filter-sludge, blow out the jelly carburetor, make sure that the air hole in the tank lid is not clogged.
- 💨 No compression: If the candle is dry and there is a spark, but the motor does not grasp, compression may be lost due to wear of the piston rings or crankshaft glands.
Owners may also experience overheating, and in addition to the aforementioned contamination of water intakes, the cause may be the destruction of the impeller pump, rubber impeller over time bluffs or wears out, stop pumping water, it is recommended to change the pump prophylactic once every 2-3 seasons of active use.
80 percent of the problems with the start-up and operation of the Kamisu Sea Pro 9.8 two-stroke engine are related to the quality of the fuel mixture and the state of the spark plug. Always start your diagnosis by checking these two elements.
Frequently Asked Questions (FAQ)
Which gasoline is better to use for Kamisu Sea Pro 9.8: AI-92 or AI-95?
The manufacturer allows the use of both fuels with an octane number of at least 92. However, the AI-95 often contains more alcohol additives that can aggressively affect the rubber seals of the carburetor during long-term storage. For seasonal equipment, many experts recommend a quality AI-92.
Can I keep the motor? Kamisu Sea Pro 9.8 vertically?
Long-term storage in the vertical position is not recommended, since the oil remaining in the crankcase of the gearbox can leak through the glands, and the cylinder can get water or condensate. It is best to store the motor in the working position (on the transom) or on a special stand. If this is not possible, store it horizontally on the side, but be sure to drain the fuel and oil from the gearbox.
Why does the engine smoke at idle speed?
Two-stroke engines always smoke a little, especially when warmed up or idling, due to the burning of oil. However, if the smoke becomes thick and blue, this may indicate too rich a mixture (a lot of oil in gasoline) or wear of oil removable rings.
How to Preserve the Motor for the Winter?
You have to completely extract the fuel from the carburetor (let the engine stall itself), or drain it through the drain visor of the float chamber. The gearbox should drain the transmission oil. The motor should be cleaned of dirt, the outer metal parts should be smeared with anticores and removed to a dry room. The candle should be twisted out, a little oil should be dripped into the cylinder and a few times slowly turn the crankshaft.