Review: Tohatsu 18 outboard

By: Andrew Norton

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  • Trade-A-Boat

How does a Tohatsu outboard compete against a motorbike and pool table? It does better at sea if it's the Tohatsu 18.

Review: Tohatsu 18 outboard
Running the Tohatsu 18 carbie two-stroke outboard on premium (95) unleaded can reduce oil smoke.

Two years ago I lamented that my friend Kim’s 2009 Tohatsu 18 had been cast aside in favour of a pool table. Now the 18 has to compete with Kim’s latest toy — a Honda CB125R learner road bike — which admittedly, is a bit nicer to sit astride than the outboard. These new toys live in the garage, while the 18 sits outside, awaiting a run. But it never complains and always starts first pull.

 

TOHATSU 18 DESIGN

The current Tohatsu M18E2 version of this enduring model (first sold more than 30 years ago) was released on the Aussie market in 1998. Unlike the popular Tohatsu M9.8 counterpart, the 18 was developed for commercial usage and features a sub cooling water intake under the anti-ventilation plate, a thermostat that can be replaced without removing the cylinder head, rod-operated throttle linkages and a bowl-type fuel filter. As with most carbie two-stroke Tohatsus the 18 has a side gear shift.

The OEDA one-star Tohatsu 18 develops 17.7hp at 5500rpm with a Wide Open Throttle range of 5200 to 5800rpm from its 294cc loop-charged powerhead and produces way more midrange torque than the direct competition. Like many engines in this power range there’s mechanical ignition timing advance but this is easily reached for tune-ups.

A six amp unregulated alternator is optional on the Tohatsu 18 outboard and the gear ratio is 1.85:1 as the 18 was designed more for planing hulls. The dry short shaft weight is 41kg. Servicing intervals are every 50 hours or annually after the first ten hours and the warranty for recreational anglers is three years.

 

POWER AND HANDLING

Looking back, I’m glad I recommended to Kim that she buy the Tohatsu 18 over the opposition. It can plane three adults where others would struggle and it’s well matched to a 1980s model 3.8m Savage Snipe tinny. As this relatively deep deadrise hull has a short shaft transom, more weight would seriously reduce freeboard aft.

This year the engine has been run about every three months, but all it needs each time is a fresh mix of standard unleaded and Valvoline Outboard 2-Stroke oil. Tape up the sub water inlet, attach the flushing ears, turn on the water, crank the engine over slowly a couple of times, then briskly pull the starter cord once and off it roars. Out comes all that wonderful blue exhaust smoke that means you’re having fun.

With the two of us plus fishing tackle aboard and swinging the standard 8.8in pitch alloy prop the Tohatsu 18 planes our 350kg total displacement on about one-third throttle opening. Adding a third light adult requires about half throttle and the Snipe still averages 18.9kts (35.1kmh) at 5300rpm. Because of the Snipe’s long keel some prop ventilation does occur through tight turns but in normal usage this is not a problem.

Corrosion has appeared in strange areas. The leg/engine pan and steering bush retaining bolts have rusted, as have the fuel pump diaphragm cover screws while bolts around the lower unit are perfect and there’s no sign of bubbling on the indigo paintwork.

 

THE TRADE-A-BOAT VERDICT

I love Tohatsu carbie two-stroke outboards. Kim’s 18hp Tohatsu has lasted so well despite its neglect, while my 2005 M8B is simply the most reliable outboard I’ve ever tested. Running carbie two-strokes on premium (95) unleaded can also reduce oil smoke and keep the spark plugs clean so the old image of smoky two-strokes simply isn’t true anymore.

As of October 2013 the short shaft model Tohatsu 18 outboard had a price of around $2600 with a spare alloy prop costing $150. For more on the 18hp visit your local Tohatsu dealer or contact Lakeside Marine, Charmhaven NSW (02) 4392 6110. 

 

PERFORMANCE

1.6kts (3.0kmh) @ 800rpm (trolling) – 0.8lt/h

10.6kts (19.7kmh) @ 3500rpm (planing)

12.9kts (23.9kmh) @ 4000rpm (cruise) – 3.9lt/h

17.6kts (32.7kmh) @ 5000rpm (max cruise) – 6.0lt/h

21.6kts (40.0kmh) @ 5800rpm (WOT) – 8.3lt/h

 

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Originally published in TrailerBoat #301, November / December 2013.

 


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