Choosing a power unit for an inflatable or light metal vessel always involves a compromise between power, weight and budget. Marlin MP 9.9 AMHS Pro This two-stroke engine is designed to meet the requirements of Russian water bodies, where it often requires a confident exit to planing with a full load of the boat.
Model AMHS Pro The company says it is a combination of reliable Chinese assembly under Marlin’s strict control and affordable price that makes it a hit, but like any other technique, it requires the right approach to operation from the first minutes of operation.
In this article, we will discuss in detail the technical nuances, hidden adjustment options and real-world experience of this unit, you will learn why many fishermen choose 9.9 hp instead of more powerful 15-horsepower counterparts, and how to properly prepare the engine for the first season.
Technical specifications and design features
Heart. Marlin MP 9.9 AMHS Pro It's a two-cylinder two-stroke internal combustion engine, and it's a classic design for this class, but it's got some important improvements. electronic ignitionIt provides a stable spark even when the battery is discharged, unlike the magdino-contact systems of older engines.
The cooling system is built on the principle of forced circulation of water through a water pump. It is important to monitor the control jet, which must be powerful and smooth. The case of the daywoot is made of durable aluminum alloy, which provides good protection of internal mechanisms against impacts on underwater obstacles. The weight of the motor in running order is about 25 kg, which is an excellent indicator for transport in the trunk of a passenger car.
Secret of Pro Labeling
In the model name, the Pro console indicates the presence of an electronic scoreboard (in some versions) and an improved lubrication system, as well as a strengthened lower unit compared to the base MP series.
The exhaust system deserves special attention, and the exhaust gases are discharged through the lower unit, which reduces the noise and vibration on the transom. carburetor set by the manufacturer to the average performance, but has screws adjusting the quality of the mixture, which allows you to adapt the engine to specific operating conditions and fuel quality.
Control system and ergonomics of the tiller
The motor is controlled by a humming device that has several degrees of freedom, and the handle is equipped with a rotary mechanism that allows you to adjust the angle of inclination for the convenience of the operator, and on the handle itself there are all the necessary controls: the gas trigger, the emergency stop crane button and the throttle handle.
Transmission gearbox Forward-Neutral-Reverse (Forward-Neutral-Back) is a rotary handle on the tiller, with a clear switch with strong position locks, minimizing the risk of accidentally turning on the rear gear on the move, a critical safety feature, especially when maneuvering in difficult conditions.
- 🔹 Ergonomics: The gas handle has a rubberized coating that prevents the hand from slipping even in wet weather.
- 🔹 Gas cable: The possibility of connecting remote control (optional) expands the possibilities of installation on boats with a console.
- 🔹 Stop tap: Emergency switch with a check is mandatory for use at each launch.
It is worth noting that the tiller force when turning the engine at high speeds can be noticeable due to the lack of a hydraulic compensator as standard, but for a 9.9 hp engine this is quite acceptable and does not cause rapid fatigue of the operator during fishing.
Fuel consumption and efficiency of operation
One of the main trump cards of two-stroke engines of the family Marlin If the carburetor is properly run and set up, the fuel consumption at full gas is about 4-5 liters per hour. At a cruising speed that is usually 3000-3500 rpm, the gasoline consumption is reduced to 2.5-3 liters.
For the preparation of the fuel mixture, AI-92 or AI-95 gasoline and high-quality two-stroke oil with marking are used. TC-W3The mixing ratio for the new engine during the break-in period is 1:25, after which they switch to the standard 1:50. The use of low-quality oil can lead to piston rings coking and engine failure.
⚠️ Warning: Never keep a motor with residues of gasoline in a carburetor for more than two weeks. The old fuel is oxidized and forms resins that clog the jellyflies, which is the most common cause of start problems.
The actual flow rate is also highly dependent on the propeller and the loading of the boat. The regular propeller is tailored for general use, but replacing it with a "speed" or "cargo" variant can change the specifications of the engine. A properly selected propeller allows the engine to operate at the optimal speed range, which directly affects resource and appetite.
The procedure of breaking in: step-by-step instructions
Quality break-in Marlin MP 9.9 AMHS Pro This is the key to a long life of the engine, and neglecting this stage often leads to bullies of the piston group, and the process of running in takes about 10 hours and should take place on a pond, not in a barrel, because the cooling system must operate normally.
☑️ Checklist before break-in
The first 2-3 hours of the engine should be operated at a speed not exceeding 2000-2500 per minute (about 30-40% of gas). At this time, the piston rings are lapped to the cylinders. Then, over the next 5 hours, you can gradually increase the load, bringing the speed to 70%, but avoiding working at full gas for a long time.
After 10 hours of operation, you need to replace the spark plug (even if the old one looks normal) and switch to a 1:50 fuel mixture. It is also recommended to check the tightening of the diewut mount bolts and transom plates, since vibration in the first hours of operation could weaken the connections.
| The break-in stage | Time (motoclock) | Working hours (gas) | Note |
|---|---|---|---|
| Initial. | 0 - 2 | 30-40% | Avoiding sharp throttle openings |
| Basic | 2 - 8 | 50-70% | Short-term accelerations up to 80% |
| Finished | 8 - 10 | 80-90% | Work at variable speeds |
| Completion | 10+ | 100% | Switch to 1:50 mix |
The main rule of running is not to give the motor a long time to work in one mode, constantly change the load so that the rings are erased over the entire surface of the cylinder.
Setup of the carburetor and elimination
Factory setting of the carburetor Marlin MP 9.9 However, when operating in highlands or using fuel with an octane number other than recommended, adjustment may be required. A carburetor usually has two propellers: an idling screw and a mixture quality screw.
If the engine stalls when the gas is opened sharply or at idle speeds it is unstable, perhaps the mixture is too poor. The rich mixture, on the contrary, causes black smoke from the exhaust and soak on the candle. Adjustment should be done carefully, making a quarter of the turn of the quality screw, and be sure to check the result under load.
⚠️ Warning: Before adjusting the carburetor, make sure that the fuel system does not have an air suction. The air suction makes any adjustment pointless and can cause the piston to burn due to dilution of the mixture.
A common problem can also be contamination of the fuel filter-sludge. AMHS Pro There's a filtration system, but when you refuel from questionable sources, it gets clogged quickly, and cleaning the sediment glass at the bottom of the fuel pump regularly will save you most of the fuel supply problems.
Comparison with competitors and final conclusions
In its price segment Marlin MP 9.9 AMHS Pro It competes with brands like Tohatsu, Hidea and Parsun, and Marlin's main advantage is its extensive service network and availability of parts. Unlike some Chinese nounaimes, Marlin is easy to find piston bands, carburetors and lower units.
The engine is perfect for PVC boats ranging in length from 3.2 to 3.8 meters. It provides confident planing with two passengers and equipment. For metal boats Kazanka or Crimea, this engine will be an excellent option for quiet movement and trolling, although it will be more difficult for him to bring the heavy hull to plane.
When preserving the engine for the winter, be sure to blow the carburetor to a complete stop of the engine so that there is no gasoline inside, and lubricate the cylinders with oil through the candle hole.
In summary, it can be said that Marlin MP 9.9 AMHS Pro It is not without the disadvantages inherent in two-stroke technology (noise, the need to mix oil), but offers reliability and maintainability, which are often more important than excess horsepower.
Frequently Asked Questions (FAQ)
Which screw is better to put for an inflatable boat 3.6m?
For a boat with a length of 3.6 meters with two passengers, the optimal would be a regular propeller with a pitch of 9-10 inches. If the boat is heavy or you plan to fish with a full load, you can consider a propeller with 8 inches increments to improve traction at the start.
Can this motor be used for trolling?
Yeah, Marlin MP 9.9 It's great for trolling. It has steady idling speeds. To adjust the speed more accurately, it's recommended to use a small pitch screw or a special trolling screw so that the engine doesn't stall at minimum rpm.
How often should you change the oil in the gearbox?
The oil in the gearbox is recommended to be changed after the first 10 motor hours (after running), and then once a season or every 100 motor hours. The color of the oil should be transparent or slightly yellowish; if it has become milky, then water has entered the gearbox and the oils need to be replaced.
Why does the engine smoke white smoke?
White smoke is normal for a two-stroke engine, especially when warmed up, it burns the oil from the fuel mixture, but if the smoke becomes thick and blue, and the oil consumption has increased dramatically, the proportions of the mixture may have been disturbed or the crankshaft glands worn out.