Outboard Engines 135-250hp

In the 135-250hp range two-strokes are the only choice and of these there's a wide choice, with direct-injection engines making up about half of the models. All models have loop-charged powerheads and some form of oil-injection. The recommended retail prices listed were current as of June 2000 and include GST unless otherwise specified.

Mercury Marine
Marketing its models under the Mariner and Mercury brand names, Mercury Marine offers carburetted, EFI and Direct Fuel Injection (DFI) Optimax models, the widest choice of fuel induction methods on the Aussie market.

Both the carbie and standard EFI models use variable ratio oil-injection where the oil is injected at the fuel pump and varies from 50:1 at Wide Open Throttle (WOT) to 100:1 at Dead Slow Troll (DST). The EFI models inject fuel at the reed valves, whereas Optimax models inject fuel directly into the combustion chamber along with pressurised air for a complete burn. The oil-injection system is designed to operate from 44:1 at WOT to 400:1 at DST, though currently these ratios are a little richer.

Carbie and EFI models idle at about 800rpm in gear, whereas Optimax models idle at 550rpm in or out of gear. All models have 60| V-six powerheads.

Smallest of the range until just recently was the long-running 135, replaced by the carburetted V-six 140hp. The 135 Optimax remains as the smallest of its DFI models in this range.

The 140 V-six carbie has a 2507cc powerhead, weighs 184kg in longshaft form and has a 1.87:1 gear ratio. It's available in long, extralong and extralong counter-rotation versions.

The 135 Optimax is available in the same configurations but has a 2507cc powerhead (a bored-out version of the 1998cc unit) and weighs 210kg in longshaft form. It retails for $15,600. (Please note, all Mercury prices quoted here do not include GST.)

Mounted on a 5.2m Haines Signature 520R and spinning a 19-inch Laser 11 stainless steel prop, the test Optimax 135 handled an estimated 950kg total (including two adults) with ease. It cruised effortlessly at 4000rpm and 56.4kmh and wound out to 80.5kmh on 5400rpm, consuming 48lt/hr.

Next up is the 150, available in EFI and Optimax versions in long, extralong and extralong counter-rotation shaft lengths. The EFI version has the 1998cc powerhead, weighs 186kg in longshaft form and has a 2:1 gear ratio. The longshaft retails for $16,560.

The 150 Optimax is an up-rated version of its 135 counterpart and has the same powerhead and gear ratio. It weighs 210kg in longshaft form and retails for $18,700.

The 175 is available in carburetted and EFI versions and long, extralong and extralong counter-rotation shaft lengths. Both utilise the 2507cc powerhead from the 135/150 Optimax. The longshaft carbie 175 weighs 180kg, has a 1.87:1 gear ratio and retails for $16,540, while the EFI version weighs 186kg, retails for $17,420 and has the same gear ratio.

Mounted on a 6.2m Markham Bonito Profish 622 and spinning an 18-inch pitch stainless steel prop, the test EFI 175 planed the estimated 1350kg total (including two adults) at 2800rpm and 30kmh, while at 4000rpm it averaged 52kmh, consuming 41lt/hr.

The WOT average was 80kmh on 5500rpm while consuming 69lt/hr.

The 200 is available in carbie, EFI and Optimax versions and shaft lengths from long to extra-extralong with counter-rotation on the extralong and extra-extralong models. The carbie and EFI versions have the 2507cc powerhead, while Optimax versions have a 3044cc powerhead.

The carbie 200 long weighs 180kg, has a 1.87:1 gear ratio and retails for $18,180, whereas the extralong carbie 200 costs $18,380.

On an Arizona Picklefork 565 skiboat, spinning a 25-inch Laser 11 prop and pushing a total of 730kg (including two adults), the 200 long achieved a clean plane on 1800rpm and cruised effortlessly at 37kmh on 2000rpm. At 4000rpm the average was 77kmh and at WOT 127kmh on an estimated 6600rpm, consuming 82-85lt/hr.

The extralong EFI 200 weighs 190kg, has the same gear ratio and retails for $19,050, while the extralong 200 Optimax weighs 225kg, has a 1.64:1 ratio and costs $21,810.

Available in EFI and Optimax versions, the 225 is available in the same shaft lengths and prop rotation configurations as the 200. Both use the 3044cc powerhead and have the same 1.64:1 gear ratio. In extralong form the EFI 225 weighs 200kg and retails for $20,530, while the extralong 225 Optimax weighs 230kg and costs $23,610.

An EFI 250 is available in extralong and extra-extralong normal and counter-rotation versions. It uses the 3044cc powerhead and has a 1.75:1 gear ratio. In standard extralong form it retails for $21,850.

All Mercury Marine outboards in this power range used in recreational applications have a two-year general warranty, three years' coverage against corrosion perforation and four years against ignition component failure.

OMC
Since its well-publicised separation of brand names in mid '98, OMC has offered carburetted Johnsons, with the FICHT Fuel Injection versions being Evinrudes.

All models except for the 250 are available in both versions and all models have V-six powerheads but the 150 and 175 have a 60| vee, while the 200, 225 and 250 have a 90| vee.

The FICHTs use a reasonably high pressure fuel system which injects fuel directly into the combustion chambers at 250psi, higher than the Optimax system but with less overall complication. At low speeds (under about 2500rpm) the combustion chamber air/fuel ratio is stratified or 'layered' to as lean as about 40:1 away from the spark plug, but over these revs homogenous combustion occurs and the air/fuel ratio is about 25:1. This gives sufficient fuel for excellent mid-range performance, but enables the FICHTs to run very lean and clean when trolling.

Johnsons have a fixed 60:1 ratio Oil Management System which injects oil at the fuel pump, whereas the FICHTs have a separate oil delivery system with designed ratios from 60:1 at WOT down to 300:1 at DST. In reality these ratios are currently a little richer.

The Johnsons idle at about 800rpm in gear, while the FICHTs idle at 650-800rpm in or out of gear, depending on the model.

Smallest of the range in this category is the 150, which uses a 2589cc powerhead. It's available in long, extralong and extra-extralong counter-rotation models and has a 1.86:1 gear ratio. The carbie 150 long weighs 168kg and retails for $15,550, while the FICHT 150 long weighs 184kg and costs $17,240.

Mounted on a 6.0m Seafarer Victory, spinning an 18-inch stainless steel prop and pushing a total of 1500kg (including three adults), the demo FICHT 150 wound out to 74kmh, consuming 49lt/hr.

The 175 uses the same 2589cc powerhead and 1.86:1 gear ratio and is available in the same selection of shaft lengths. The carbie 175 long weighs 168kg and retails for $15,970, while the FICHT 175 long weighs 184kg and costs $17,230.

The 200 uses a 3000cc powerhead, has a 1.86:1 gear ratio and is available in extralong and extra-extralong shaft lengths with counter-rotation options on both models. The extralong carbie 200 weighs 206kg and costs $17,300, whereas the extralong FICHT 200 weighs 21kg and retails for $18,700.

Again having the same powerhead, gear ratio and weights the 225 is available in longshaft carbie form in addition to the shaft lengths/prop rotation options of the 200. The extralong carbie 225 retails for $19,110, and the FICHT version $21,210.

Mounted on a 5.9m Seafarer Vermont and spinning a 20-inch stainless steel prop, the demo extralong FICHT 225 planed the 1500kg total (including three adults) at 34kmh on 2800rpm. At 4000rpm the average was 61kmh, consuming 50lt/hr, and at 5400rpm the WOT average was 88kmh and 80lt/hr.

The Johnson 250 is OMC's most powerful outboard and has four dual-throat carbies. It has the same powerhead and gear ratio as the 225 and is available in extralong and extra-extralong models, both with counter-rotation if needed. In extralong form it weighs 208kg and retails for $20,990.

Mounted on the same Vermont and spinning a 22-inch stainless steel prop, the demo extralong 250 planed the 1500kg total at 35kmh on 2200rpm. At 4000rpm the average was 68kmh and 65lt/hr, while at WOT it averaged 92kmh and 110lt/hr on 5400rpm.

All Johnson and Evinrude outboards have a two-year warranty coverage for recreational users.

Tohatsu
There's just one model in the Tohatsu line-up in this power range, the M140A2, which is available in long and extralong versions. It's the only straight four and displaces 1768cc. It has a 2:1 gear ratio, weighs 150kg in longshaft form and retails for $12,300.

The 140 was released locally in 1991 and has proven particularly reliable in commercial applications, although the absence of a counter-rotation model is a real drawback. The inline cylinder configuration makes the engine very easy to work on, and the variable ratio oil-injection operates at 50:1 at WOT down to 100:1 at DST.

Mounted on a 5.0m Success Craft skiboat and spinning a 21-inch Laser 11 prop, the demo longshaft 140 pushed the 700kg total (including two adults) to 85kmh on 5500rpm consuming 55lt/hr. The warranty is two years for recreational users.

Yamaha
Though still lagging behind its US competition in offering low-pollution two-strokes, Yamaha is rapidly catching up.

The company now has a mix of carbie, EFI and DFI models. All of these have V-six powerheads, but the 150, 175 and 200 carbie models have a 90| vee, while the Z200N and 225 have a 76| vee.

All engines have variable oil-injection, where oil is injected at the reed valves via individual feed lines, from 50:1 at WOT down to 200:1 at DST. This system eliminates having to run the carbies dry before storage but does prevent the butterfly throttle valves from receiving lubrication, leading to possible verdigris build-up. It's also intolerant of 'gelling' in the feed lines from mixing different brands of oil.

The range starts at the 2596cc 150, which is available in long, extralong and extralong counter-rotation models. The gear ratio is 1.86:1 and the longshaft version weighs 191kg and retails for $16,240.

(Please note, all retail prices quoted here do not include GST. Yamaha was still finalising its GST pricing as this issue went to press.)

Next is the 175, which utilises the same powerhead and gear ratio but is only available in extralong form. It weighs 195kg and retails for $17,750.

Mounted on a Southwind SF655 and spinning a 17-inch stainless steel prop, it pushed the 1500kg total (including two adults) to 76kmh on 5500rpm, consuming 71lt/hr.

Although all versions of the 200 have a 2596cc powerhead and a 1.86:1 gear ratio, the Z200N has a 76| vee instead of the 90| angle. The carbie 200 is available in only extralong form with counter-rotation option, while the Z200N comes in long and extralong models. The extralong carbie 200 weighs 195kg and retails for $18,380.

The Z200N is Yamaha's first outboard to use High Pressure Direct Injection (HPDI), where fuel pressure is raised via three pumps to 750psi by the time it reaches the combustion chamber. Unlike the US competition, it uses a modified Mitsubishi automotive fuel-injection system and automotive spark plugs, and unlike the OMC FICHT system, has only homogenous combustion (20-25:1) across the entire rev range. Yamaha reasons that with the fine atomisation of fuel, there's no need for stratified combustion at low revs. Unusually, the engine also idles on four cylinders, with the others firing up when forward or reverse gear is selected.

In extralong form the Z200N weighs 220kg and retails for around $25,000. Mounted on a Southwind SF655 and spinning a 17-inch stainless steel prop, the demo extralong planed the 1650kg total (including four adults) at 31.9kmh on 3000rpm and cruised very quietly at 4000rpm and 55kmh. The WOT average was 80.9kmh and 5800rpm where it used 68lt/hr 16% less than a carbie 200.

De-rated versions of the Z200N, known as the Z150P and Z175G, were released in June this year.

Mounted on a Southwind SF550WR Walkaround, spinning a 17-inch stainless steel prop and pushing a total of 1500kg (including four adults), the demo Z150P averaged 7.2kmh on 1000rpm, consuming a mere 5.4lt/hr, and cruised quietly at 59kmh on 4000rpm, using 25.6lt/hr. The WOT average was 78.7kmh on 5600rpm, consuming 56.6lt/hr 22% less than what the carburetted 150 would have used.

The Z175G develops the extra power from modifications to the electronic management system.

Yamaha's largest engines are the 225 and 250, both utilising a 76| V-six, 3130cc powerhead stroked from the Z200N's 2596cc unit. The engines are available in carbie (six individual units) and EFI variants and extralong, extra-extralong and counter-rotating models. All have a 1.81:1 gear ratio and like the Z150P/Z175G/Z200N models, idle on four cylinders.

Mounted on a Cruise Craft Outsider 685, spinning a 19-inch stainless prop and pushing a total of two tonnes (including four adults), the demo EFI 250 planed us at only 27.4kmh on 2700rpm and cruised effortlessly at 58kmh on 4000rpm. The WOT average was 80.5kmh on 5400rpm, consuming 107lt/hr 4% less than what the carburetted 250 would have used.

The extralong carbie 225 weighs 236kg, while the extralong EFI 250 weighs 237kg.

PICK OF THE BUNCH
It's a toss-up between the Optimax 135/150 and FICHT 150 as each have their own good and not-so-good points. The Optimax engines are heavier and more complex, but troll at lower revs and have the Electronic Control Unit located in a more logical position, away from possible heat sink.

The Yamaha Z150P should provide strong competition to its FICHT and Optimax rivals, but time will tell how well this engine compares.

Around 200hp my choice is the FICHT 225, which performs almost as well as its Johnson 250 counterpart but is substantially more fuel efficient. And Yamaha's Z200N shows great potential because it's much more frugal than the carbie 200 and provides excellent mid-range performance in a package that's lighter than its Optimax competition.