What year did merc start Direct injection

[JR250SHO]

What year did merc start Direct injection as opposed to feeding fuel thru the intake? 2002 on opti, but what about the rest? The reason I ask is I am in the market for a new motor (250-300 range) and am trying to figure out which is the best for me. Is the DFI the way to go or not that much different from the intake feed? A lot better fuel economy? Whats the scoop?

[EuropeanAM]

The Optimax technology was initially out in 1997, with multiple Optimax models in 1998.

Compared to a "traditional Intake-fed EFI".... there's a SUBSTANTIAL advantage (fuel economy and emissions) to the Direct Injected models... a MINIMUM of 33% less fuel consumed (in some cases, up to 50%)!

[JR250SHO]

So all the opti were/are cylinder injected and not intake injected? And all the efi's are intake injected. What about the 250xs's, 300x, 300xs, 250's etc...

[esdbass]

300X is a EFI motor the 300XS and 250XS are DFI motors

[EuropeanAM]

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jr225ho &raquo;</TD></TR><TR><TD CLASS="quote">So all the opti were/are cylinder injected and not intake injected? And all the efi's are intake injected. What about the 250xs's, 300x, 300xs, 250's etc...</TD></TR></TABLE>

In general, all "EFI" designated models are "intake injected". In other words, injectors were placed in or near the reed blocks to "similate" carb operation. This includes EFI models, 250XB, 225X, 300X, and several others in the "past" 3L lineup.

All of the Optimax, XS, and ProXS models are "Direct Injected Two Strokes" (DFI).

The increase in fuel economy is primarily related to the injection of fuel DIRECTLY into the cylinder, AT, or just after the point that the piston covers the exhaust port (eliminating the escape of unburnt fuel out the exhaust). This change (in and of itself) accounts for approximately a 33% improvement in fuel economy (which is BEFORE other improvements are taken into consideration).