Merc Opti`s

[LubeDude]

I learned a lot about the early Merc 150`s having had one for the last three years. Now I`m contemplating an Optimax.

What can you tell me about the oiling system, does the oil mix with the fuel and then through the injectors, or is it a more direct injection system?

 

[LubeDude]

Re: Merc Opti`s

I guess I have answered my own question. It appears that the EFI`s were more like a throtlebody injection system and the OPti`s are direct injection with the fuel not mixing with oil before going through the injectors, am I correct?

 

[WillyBWright]

Re: Merc Opti`s

Yup.

 

[Chris1956]

Re: Merc Opti`s

Lubedude, From what I understand, the Opti's have a two-stage direct injection design. A low pressure fuel pump injects gasoline into a chamber near the cylinderhead. Then a high pressure blast of air (from a compressor) forces the fuel into the combustion chamber, after the piston has closed the exhaust and intake ports. The oiling system works by mixing a bit of oil with the air intake through the throttle body and reed valves.

It differs from the Evinrude E-TEC, in that Opti uses high pressure air to achieve direct injection, whereas the E-TEC uses a single stage high pressure fuel pump to inject the gasoline into the combution chamber.