OMC Evinrude's FICHT RAM 135

The Evinrude FICHT RAM 135 combines tons of grunt with great fuel economy, reports Andrew Norton...

OMC has released a motor that competes directly with Mercury Marine's frugal Optimax 135. Yet it weighs a claimed 10% less for comparable performance.

The FICHT 135 is a de-rated version of the FICHT 150/175. One of the first models to be introduced from scratch with the FICHT 'RAM' modifications already engineered in, it has missed out on the problems that afflicted the early 150/175, such as rapid combustion chamber carboning up.

The RAM system includes features such as cooling water being directed over the cylinder exhaust ports to reduce temperature in this region. The same amount of water is directed to each cylinder bank to prevent hotspots between the banks.

For increased lubrication under load and to reduce cyl inder wall temperatures, piston ring and bore wear, a cylinder sleeve oiling system has been added with a hole in each piston skirt below the lower piston ring. The pressurised oil is also injected at the crankshaft and wrist pin bearings for less friction under load.

Other changes include a higher pressure oil pump and revised oil recirculation.

The combustion chambers were modified to include deflectors to direct fuel spray away from the spark plugs and OMC used a Sagem Inc 'toe seat' injector for better sealing during the injector stroke and more consistent spray patterns.

The spark plugs have a stepped centre electrode with very narrow platinum tip to extend plug lifespan and prevent late combustion due to carbon deposits.

OMC reprogrammed the Electronic Control Unit (ECU) to lower the revs where the engine switched from stratified to homogenous combustion down from about 2800 to 2000. At low revs the stratified or 'layered' levels of air/fuel mix are about 40:1 but as the torque band comes in, homogenous mixing takes over and the air/fuel ratio increases to about 25:1.

The ECU programming was also modified to supply less fuel than before above 1500 revs when there's more exhaust back pressure and more fuel when there's less pressure, reducing exhaust emissions under varying load conditions.

Finally there's Evinrude FICHT RAM oil, which I've been evaluating since February last year in a variety of engines. This is a semi-synthetic blend with a heavy-duty solvent that dissolves carbon deposits and holds them in suspension where they are expelled with the exhaust gases. According to OMC, FICHT RAM Oil is 2.6 times more effective in reducing carbon deposits than the normal TC-W3 solvent additives package.

And how do all these modifications shape up?

Very well, if the demo FICHT 135 was anything to go by. The motor started instantly hot or cold, in fact much faster than an Optimax 135 and had an incredibly smooth idle in or out of gear at the minimum revs of 900.

At no time did oil smoke appear, only some oil smell when the motor was running double the normal fuel/oil ratio (first five hours) and accelerated rapidly astern. Unlike early-model FICHTs there was absolutely no hesitation where the engine switches from stratified to homogenous combustion.

Fitted to Ally Craft's recently-released 733 Tomahawk and spinning a 17-inch stainless steel prop the demo 135 provided a good blend of bottom-end torque and stunning acceleration above 4000 revs.

Pushing a total of 1320kg (including three adults), according to the Lowrance GPS/plotter fitted the 135 trolled us at 5.5kmh on 900 revs. It planed us cleanly at 26.9kmh on 3000 revs and maintained an effortless cruise at 45.7kmh on 4000 revs, consuming 24lt/hr. At Wide Open Throttle (WOT) we averaged 67.9kmh on 5450 revs over a sizeable chop on Lake Macquarie, consuming 47lt/hr. The motor was also significantly quieter than Optimax 135s I've tested in the past.

Servicing the FICHT 135 appears straightforward with recommended intervals every 100 operating hours or once a year (including the waterpump impeller) after the first 20 hours or three months.

All I can conclude is that it's now going to be very hard for prospective 135hp owners to choose between the Optimax and the FICHT!