Choosing an outboard motor for a PVC inflatable boat or a light boat is always a compromise between price, weight and reliability. Golfstream T9.9BMSThis unit is often seen as an alternative to more expensive brands like Tohatsu or Mercury, looking for affordability and maintainability. The Russian boating market is full of offers, but it is the Chinese who gather the most controversy and discussion around them.
Many water-engineers are wondering whether to connect with products assembled in China, or better to overpay for Japanese origin? Gulfstream 9.9 This is due not only to its low cost, but also to a time-tested design that goes back to Yamaha’s licensed designs, but like any technology, it has its own nuances of operation, which are not mentioned in dealer brochures.
In this article, we will take a closer look at the actual experience of operation, collecting and systematizing the opinions of users who have already passed the test stage and run hundreds of motorcycle hours, we will touch on the technical features, frequent breakdowns and, of course, the popular question of swelling up to 15 horsepower.
Technical features and design of the engine
Engine. T9.9BMS It's a classic loop-blown two-stroke unit, built on a proven 246 cubic centimeter cylinder block, which provides the engine with high torque at low revs, which is critical for sleeve-to-rolling with a full boat load.
One of the key features is the presence of a system. electronic ignitionThis allows the engine to operate consistently at idle speeds without the need for constant gagging, which is especially true when trolling or maneuvering in the port. The Mikuni carburetor installed in the factory, when properly set up, provides relatively uniform mixture formation, although the quality of its operation often depends on the quality of the fuel.
- 🔹 Lubrication system: mixing oil with gasoline in a ratio of 1:50, which requires careful refueling.
- 🔹 Cooling: forced water, through the off-shore water, with a control hole ("control") for visual check of circulation.
- 🔹 Spin transmission: through a conical gear in lower unit, which provides reverse and neutral.
⚠️ Warning: Unlike the four-stroke counterparts, the two-stroke Gulf Stream requires the mandatory addition of a special two-stroke oil to gasoline. Working on pure gasoline is guaranteed to lead to a bully of the piston group within minutes.
The weight of the engine in running order is about 36 kilograms, which is quite a lot for a motor of this power compared to modern four-strokes, but for two-stroke classics, the indicator is standard. Metal lower unit and crankcase give the structure massiveness, but at the same time increase its survivability when hitting underwater obstacles.
real owner reviews: pros and cons of operation
And by analyzing forums and user reports, you can see a strong pool of opinions, and owners often point out that the engine starts off the hook after running it right, but there are also people who have had problems in the first season, and let's structure that experience so you can make an informed decision.
K positives The boat with this engine is 3.2-3.6 meters long and even planing with two adult passengers, and the availability of spare parts is also praised: unlike rare brands, parts on the Gulf Stream can be found in almost any service dealing with the Chinese.
However, negative There are also complaints about the backbone, which you have to choose yourself, pulling bolts and adding lubricant. The quality of bolt joints often leaves much to be desired - owners recommend immediately after purchase to carry out a full stretch of all the nodes.
- 🔸 Frequent problem: spontaneous unscrewing of carburetor screws due to vibration, requires fixation of the thread.
- 🔸 Nuance: Sometimes there is poor-quality processing of lower unit, which can lead to corrosion if you do not cover the metal with anticores.
- 🔸 Ergonomics: The handle of the tiller can seem stiff and uncomfortable for long transitions without reworking.
Importantly, many of the complaints are related to the initial setup: the engine comes with basic adjustments that may not be appropriate for the specific operating conditions or fuel used. Properly tuning the carburetor can do wonders by eliminating dips and improving sensibility.
The process of breaking in: instructions and typical errors
The break-in is the most important stage in the life of any new engine, and Golfstream 9.9 And the basic purpose of this period is to rub the piston rings against the cylinder walls and ensure that the rubbing pairs wear uniformly.
The process takes about 10 hours of operation. The first 2 hours (one tank of fuel) is recommended to operate the engine at idling or at minimum speeds, not exceeding 2000-2500 rpm. forbidden The mixture should be slightly richer than usual, so many mechanics recommend adding oils slightly above normal (for example, 1:40) only to the first tank.
☑️ Checklist of proper breaking in
⚠️ Warning: Never keep the motor at full speed during the break-in process. This will cause the piston to overheat, as the gaps have not yet reached operating values, and the heat sink will be disrupted.
After the first 2-3 tanks are developed, you can gradually increase the load by adding 1,000 revolutions to each subsequent fuel tank. By the 10th hour of operation, the throttle is allowed to open at full capacity for a short time. It is also important to monitor the temperature of the case and the presence of a jet of water from the control hole during this period.
At the end of the break-in necessarily You need to replace the spark plug and preferably maintain the gearbox by checking the oil for emulsion. Some owners also recommend replacing the fuel filters, as they can settle dirt washed from the tank during active operation.
Tuning and increasing power to 15 hp
One of the most discussed issues in the community of boaters is the possibility of reworking. Golfstream 9.9 The 15-horsepower version is technically possible, because the 9.9 and 15-hp cylinder blocks are often identical, and the difference lies in the constraints that the manufacturer has set for environmental compliance or marketing positioning.
The main method of increasing power is to squander the petal valve(s) and change the setting of the carburetor. In the runoff state, the petals can be mechanically limited or have a smaller opening area. Removing the limiters allows you to increase the supply of fuel and air mixture into the cylinders.
Technical details of the alteration
Reworking usually requires removing the carburetor, dismantling the petal valve and gently scattering it on an sandpaper or by hand, increasing the through section, and often changing the carburetor chillers to more productive ones.
But you have to understand the risks. The power increase increases the heat load on the piston group. If the standard materials are designed for 9.9 hp, then working at the limit can reduce the engine life. Automatically removes the engine from the warranty.
- 🚀 Spreading petals: increases the filling capacity of the cylinders, adds "top".
- ⚙️ Customization of the carburetor: requires accuracy, otherwise overheating or loss of traction at the bottom is possible.
- 🔧 Rotor replacement: Installation of a screw with a large pitch can improve speed, but will load the crankshaft.
Many users note that even without a full-fledged alteration, simply choosing the optimal screw and adjusting the carburetor for a specific boat, you can achieve a speed increase of 2-3 km / h.
Comparison with competitors: Tohatsu, Yamaha, Hidea
To understand the Gulf Stream's market position, you need to compare it to direct competitors, most often compared to the Tohatsu M9.9B, Hidea HD9.9FHS and older Yamaha models. Let's look at the key performance comparison table.
| Characterization | Golfstream T9.9 | Tohatsu M9.9 | Hidea HD9.9 |
|---|---|---|---|
| Workload | 246 cm | 169 cm | 246 cm |
| Weight (kg) | 36 | 36 | 37 |
| Ignition system | CDI (electronic) | CDI (electronic) | CDI (electronic) |
| Price (orient.) | Low. | High. | Medium |
As you can see from the table, Gulfstream and Hidea They have almost identical specifications, as they are often assembled in the same plants (Parsun or similar), Tohatsu in this comparison stands out for smaller volume, but the Japanese quality of assembly and materials, but the price of a Japanese brand can be one and a half to two times higher.
Owners who switched from the Yamaha 9.9 to the Golfstream often note the greater noise of the Chinese unit. Japanese engines are quieter and softer due to better knee-shaft balancing and better casting quality. But in terms of pure traction and drag ability, there is little difference.
The 9.9 Gulf Stream is the best choice for those looking for maximum power for minimal money and willing to put up with a slightly higher level of noise and vibration compared to premium brands.
Maintenance and common malfunctions
The engine's life is directly dependent on the quality of service. Two-stroke technology does not forgive savings on consumables. Regular replacement of candles, checking fuel filters and grease of lower unit are the minimum required. Many problems can be prevented by simply following the rules.
One of the frequent failures is carburettorThis is because of the use of poor quality gasoline or the storage of the engine with the residue of fuel in the float chamber, before long storage (in winter) be sure to exhaust all the gasoline from the system before the engine dies.
Also worth mentioning is the problem with the lower unit, which is that some of the specimens have water sucking through the oal of the paddle shaft, which causes an emulsion (white slurry) in the gearbox, and if you don't notice and replace the oels in time, the gears of the gearbox can rust or get bullied because of the lack of lubrication.
- 🛠 Prevention: Lubricate the turning mechanism of lower unit with lithium lubrication every 10 motor hours.
- 🛠 Fuel: Use AI-95 gasoline and quality oil for two-stroke engines (JASO FC/FD).
- 🛠 Storage: Keep the motor strictly upright so that oil does not leak out of the gearbox.
⚠️ Attention: If you experience a knock or a sudden loss of power, immediately turn off the engine. Further work may lead to the destruction of the rod or crankshaft, which is not economically feasible to repair.
To diagnose many problems, it is useful for owners to have a manual with electrical circuits and a bolt tightening table on hand. Although the design is simple, the accuracy of the assembly is important. For example, the wrong moment of tightening the cylinder head can lead to gasket failure and loss of compression.
Summary: Is it worth buying?
Summing up the review, it can be said that Golfstream T9.9BMS It's a workhorse for the Russian fisherman and tourist, and it's not without the disadvantages of the budget segment, but it offers a great value for money, it's a motor for those who can work with their hands and understand the principles of the engine.
If you want a 10-year, uninterrupted, put-and-forget engine, you might want to look at more expensive four-stroke models or Japanese classics, but if you have a budget and you need power here and now, the 9.9 Gulf Stream is a reliable assistant that, if properly maintained, will last many seasons.
When buying a used Gulf Stream engine, be sure to check the compression. A value below 8 atmospheres indicates serious wear of the piston group and the need for major repairs.
Remember, the right running and the right fuel work wonders with even the simplest of machines, and thousands of happy owners across the country are using these engines for fishing, hunting and cruising, proving that a Chinese can be as good as a Japanese when approached correctly.
Which screw is better to put for a PVC boat 3.2 meters?
For a boat with a length of 3.2 meters with one passenger, a regular propeller is usually enough. If the boat is loaded (2 people + cargo), it is recommended to put the propeller with a step of less than 1-2 inches (for example, 8 instead of 10) so that the engine does not “snarl” idle and quickly output to the plane.
Can I use the 9.9 Gulf Stream on a boat?
Yes, it is possible if the weight of the boat does not exceed 300-350 kg, However, for heavy metal boats, 9.9 hp power may not be enough for planing, and the engine will operate in a constant overload mode, which will reduce its resource.
How often do you change the oil in the gearbox?
The oil in the gearbox is recommended to be changed once a season or every 100 motor hours. At the first service after running (the first 10 hours), it is better to replace it necessarily to remove the products of the primary grinding of the gears.