The search for a reliable outboard motor for a PVC boat or boat often leads to a used market. In the 18-20 hp segment, the Japanese company is considered the undisputed leader. TohatsuThe engine is famous for its indestructibility and simplicity of design, and buying a used version saves up to 40% of the cost of a new unit while getting time-tested equipment, but the market is saturated with offers of varying degrees of safety, and an inexperienced boating risks buying a problematic one.
In this article, we will discuss in detail what to look for when inspecting, how to distinguish the original from a fake or a restored "designer", and whether it is worth contacting after-service engines at all. MFS18C and two-stroke analogues, so that your investment will be profitable.
Why Tohatsu 18 hp: analysis of popularity on the secondaryThe 18 horsepower model occupies a unique niche in the outboard motor line, a threshold that allows the use of a watercraft without mandatory registration with the GIMS (subject to long and weight conditions), which makes the demand for such engines stable high. Tohatsu I bet on minimalism: there is no complex electronics that could fail, and the cooling system is designed with a large margin of safety.
Often in the secondary market there are models of the series. MFS18C Four-strokes are valued for quiet operation and economy, while two-strokes are attractive for their ease and ability to transport in any position. The choice depends on your priorities: if you want autonomy and not mixing gasoline with oil, look towards the 4T. If the weight of the motor for carrying by hand is critical, the two-stroke option will be preferred.
Where to look for ads: sites and risks of fraudstersSearching for a good copy is a time-consuming process. The main advertising platforms are specialized powerboating forums, general message boards and social networks. In forums, the likelihood of running into a dealer or a fraudster is much lower, since the reputation of users there is often confirmed by years of communication, but the range there is limited, and it will take a long time to wait for your own engine.
Bulletin boards offer a huge selection, but they require increased vigilance, and there are often ads from dealers who bring equipment from other regions or countries, and these engines can have hidden defects that will only be revealed after purchase. Check the VIN number of the engine for duplicates on the Internet. This will help to identify stolen equipment or engines that have been in serious accidents.
⚠️ Warning: Never prepay for an engine unless you've seen it live, and the photos in the ad can be taken from the Internet, and the real product will be thousands of miles away.
External inspection: what hides the paint and boltsThe first thing that catches your eye when you meet a salesman is the appearance of the unit. The presence of chips, scratches and scuffs on the lower unit and anti-cavitation stove indicates intensive operation, possibly in difficult conditions (rocky bottom, visits to unequipped shores), but the more important indicator is the condition of the fasteners. If the bolt hats on the carburetor, starter or ignition system have signs of unwinding, this is a signal that the engine has been opened.
Check the lower unit for dents and deep scratches. If the lower unit is flat, but the lower unit foot shows traces of welding or putty (you can check with a magnet if the leg is metal, or visually for unnatural bumps), it is better to refrain from buying. lower unit straightening is a complex procedure that often leads to a violation of the coaxiality of the paddle shaft and vibrations at high revs.
Pay special attention to the condition of the lower unit at the exit of the paddle shaft. The presence of a backshaft when the screw is swayed with the hand is a critical defect. This indicates wear of bearings or even bushings, the replacement of which requires a complete disassembly of the lower unit and special tools. Also check the condition of the lower unit pipe: it should not have cracks, especially in the area of the lower unit leg.
Take a powerful magnet with you to see it, and if it doesn't hold well on your lower unit leg in certain places, it might have been a body repair using a putty.
Diagnostics of the engine: compression, spark and carburetorThe heart of the motor is the cylinder-piston group (CPR). Tohatsu 18 The normal indicator of compression is the range from 10 to 12 atmospheres (kg / cm2). The scatter between the cylinders should not exceed 1 atmosphere. If the compression is below 8 atmospheres, the engine will not start well, warm up and lose power. Measurement is carried out using a compressometer, which is desirable to have with you or negotiate measurement at the service.
For two-stroke modifications, the situation is different: there is a compression lower, about 7-9 atmospheres, but the more important parameter is the tightness of the crankcase. Checking is done by applying pressure to the crankcase and diving the motor into water (or washing joints), but in the field this is difficult to do, an indirect sign of problems with the crankcase can be unstable idle and floating speeds.
☑️ Checklist for engine check
The ignition system and the carburetor also require attention. Unwrapped candles: their color should be brick-brown. Black soda indicates an over-enriched mixture or problems with ignition, white soda indicates overheating or poor mixture. carburetor motorized Tohatsu It's reliable, but if the engine was long, the jellyfish could coke in. Ask the seller to let the engine run in all modes: it must confidently gain momentum and keep idling.
Cooling system and lower unit: hidden threatsOverheating is the main enemy of any outboard motor. When checking, make sure that a stable stream of water comes from the control hole (the “urinal”). Weak pressure or its absence indicates a malfunction of the pump (impeller) or a clogging of the cooling system. On used motors, the impeller is often “clouded” or has cracks, which requires immediate replacement.
How to check the pump without disassembly?
Start the engine in a barrel of water. If the jet from the control hole is weak but the engine is not warming (check the thermostat if you have one, or pipes), perhaps the cooling channels in the block are clogged. Try washing the system with scale detergent. If it does not help, you need to disassemble.
Check the lower unit for backlashes. Swing the propeller side to side. Minimum backlash is allowed, but if it's palpable (more than 1-2 mm), it's a sign of wear on the propeller bearings or bushings. Replacing these elements is a time-consuming process that requires pressing new parts. Also check the condition of the boulders: if oil or emulsion drips from under the diewood leg, the os need to be replaced.
The table below will help to systematize the main parameters of the test:
| Verification setting | Norm for 4T Tohatsu 18 | Norm for 2T Tohatsu 18 | Critical |
|:--- |:--- |:--- |:--- |
| Compression | 10-12 atm | 7-9 atm | High |
| Exhaust colour | Transparent/Steam | Blue smoke (moderately) | Medium |
| Roller shaft | Minimum | Minimum | High |
| Cooling jet | Powerful, stable | Powerful, stable | Critical |
| Noise level | Smooth | Ring noise | Average |
Transportation and storage: nuances for used technologyWhen you plan to buy a used motor, immediately decide on the issue of its delivery and storage. Tohatsu 18 The two-stroke versions are lighter, but cannot be transported in any position due to the risk of oil leaking out of the crankcase (unless these are separate lubricants, but classic 2Ts require verticals).
⚠️ Note: When transporting a four-stroke motor, it cannot be placed on its side or upside down without first draining the oil, and the oil can enter the combustion chamber through the crankcase ventilation system, leading to hydraulic shock on the first run.
To store the engine in the off-season, you need to mothball the engine, which includes draining the fuel from the carburetor float chamber, treating the cylinders with conserved oil and storing it in a dry room. If you buy the engine in the winter, check with the seller how it was stored. Long-term storage in the open air under the tent without preservation could lead to corrosion of internal parts.
Financial aspect: is sheepskin worth making?Buying a used motor Tohatsu 18 The market price of a good one can be 60-70% of the cost of a new one, but if the engine requires a replacement of the lower unit, repair of the carburetor or replacement of the CNG, the savings quickly disappear. Tohatsu It is very high and the waiting time can be long.
On the other hand, Japanese engines have a huge resource, and there are some that, after 10 years of operation, only require replacement of candles and oil, and if you're lucky enough to find a motor from a neat owner who has changed oil according to regulations and hasn't pushed it to the limit, you'll get a reliable assistant for a reasonable price, and the main thing is to take your time and carefully check each node.
Frequently Asked Questions (FAQ)
What is the life of the Tohatsu 18 b/y outboard motor?
Four-stroke resource Tohatsu 18 With proper maintenance, it can be as long as 3,000 to 5,000 hours, two-stroke engines live a little less, about 2,000 to 3,000 hours, but depend heavily on the quality of the mixture and the operating conditions, and the key factor is timely oil change and no overheating.
Can I find parts for old Tohatsu models?
Yeah, Tohatsu Motor parts from 15 to 20 years ago are often available on stock or on order, but the prices of original parts can be high, which is worth considering when buying a cheap used engine.
Which is better: Tohatsu 18 b/w or a new Chinese engine?
It's a matter of priorities. The new Chinese will provide a guarantee and no history of service, but may be inferior in reliability and liquidity on resale. Tohatsu It's proven reliability and high residual life, but with the risk of hidden defects, Japanese is better for the pro, and maybe a new budget option with a guarantee for the beginner who is afraid of repairs.
How to distinguish the original Tohatsu from a forgery?
Pay attention to the quality of the aluminum casting (smooth, no sinks), the build quality (gaps are uniform), the presence of holograms and VIN-numbered nameplates. Counterfeits are often rough-colored, backlashes in gearshift mechanisms and no markings on important nodes.