Optimaxes

[Glastron1987]

Are Optimaxes prone to carbon buildup like what happens in direct injection car engines? If so, what extra maintenance steps would help that?

Also, what extra maintenance does an Optimax need compared to a carbed engine.

I have a mid-section nearly ready for a powerhead and I'm debating with myself whether to go carbed for the simplicity, XRI/EFI for the nice running, or full Optimax for the fuel efficiency. In any case I want reliability.

[25two.stroke]

Yes, they are prone to carbon buildup, carbon fouling plugs, carbon fouling injectors etc. The more you run them the better you are. Keep the motors running at the proper temp. Don't let the thermostats go bad and the motor run cold...it will increase the carbon buildup. Run DFI specific oil. Some have good luck with fuel cleaners like quickleen. Keep in mind an opti uses a different adapter plate than an efi/dfi

[Glastron1987]

Yes, they are prone to carbon buildup, carbon fouling plugs, carbon fouling injectors etc. The more you run them the better you are. Keep the motors running at the proper temp. Don't let the thermostats go bad and the motor run cold...it will increase the carbon buildup. Run DFI specific oil. Some have good luck with fuel cleaners like quickleen. Keep in mind an opti uses a different adapter plate than an efi/dfi

Thank you. Wow, very thorough and descriptive response. Gives me something to think about. I did notice the different adapter plate so glad to hear the confirmation on that.

[25two.stroke]

Thank you. Wow, very thorough and descriptive response. Gives me something to think about. I did notice the different adapter plate so glad to hear the confirmation on that.

Lazer efi, a brucato, a nice clean set of injectors and a set of ccms glass reeds is an ideal setup for a recreational motor. Just make sure it has steel caged bearings and premix your oil.

The only thing the opti has over an efi is a more dependable oil pump and better fuel economy at idle through midrange. If you live your life at WOT an opti will not be more fuel efficient than and efi. Neither will a fourstroke.

[Glastron1987]

Lazer efi, a brucato, a nice clean set of injectors and a set of ccms glass reeds is an ideal setup for a recreational motor. Just make sure it has steel caged bearings and premix your oil.

The only thing the opti has over an efi is a more dependable oil pump and better fuel economy at idle through midrange. If you live your life at WOT an opti will not be more fuel efficient than and efi. Neither will a fourstroke.

Oh, but I love my XR4 oil injection, it has never failed me in 37 years!

By Lazer you mean the XRI, (earlier EFI) correct?

Interesting what you said about fuel economy. I don't see a lot of testing comparisons at the different speeds. The only speed I really see a lot for fuel used on my carbed XR4 is at WOT. At low speed and mid-range I really don't see an issue with fuel usage. So that puts a good perspective on the return I'd get on the complication of an Optimax (or fourstroke).

[25two.stroke]

Oh, but I love my XR4 oil injection, it has never failed me in 37 years!

By Lazer you mean the XRI, (earlier EFI) correct?

Interesting what you said about fuel economy. I don't see a lot of testing comparisons at the different speeds. The only speed I really see a lot for fuel used on my carbed XR4 is at WOT. At low speed and mid-range I really don't see an issue with fuel usage. So that puts a good perspective on the return I'd get on the complication of an Optimax (or fourstroke).

Don't get me wrong, oil injection can work. I have spun a 2.4 with oil injection up to 7800 rpm...but that does not mean that it is smart or worth the risk. I have seen oil injection fail and kill 2 strokes as much as I have seen negligence kill motors. And a lot of people neglect their motors. I personally cannot trust something (that I know is a bad idea) to keep my motor lubricated when I could do the same myself with one simple measure and dump in the gas tank. Yeah WOT none of the motors get good fuel economy. A 260 may burn 26-30 gallons an hour at WOT...a 225 3.0L optimax 26 gph, and a 150 4stroke 23 gph...the only difference is the 260 is fast, the 225 is knid a fast and the 150 is slow. All for what, a couple gallons and hour? I HAVE seen the numbers in person on the same or similar boats. The only real savings on fuel in my mind is when a fourstroke is run at 4000 rpms and les; then it may be a bit better.

[skialot2]

Oh, but I love my XR4 oil injection, it has never failed me in 37 years!

By Lazer you mean the XRI, (earlier EFI) correct?

Interesting what you said about fuel economy. I don't see a lot of testing comparisons at the different speeds. The only speed I really see a lot for fuel used on my carbed XR4 is at WOT. At low speed and mid-range I really don't see an issue with fuel usage. So that puts a good perspective on the return I'd get on the complication of an Optimax (or fourstroke).

Mercury's oil injection system works great. Until it doesn't. I have been taking apart a bunch of junk motors lately. By far the most common failure is a bad nylon oil injection gear. The problem is the gear usually fails slowly. It's only partially stripped so the oil pump shaft rotation sensor still senses it is spinning so no alarm gets tripped. But it's not spinning fast enough to pump enough oil to properly lube the motor. By the time the gear strips completely and sets off the oil alarm it is too late. Pistons are scuffed and motor has low compression.

[XstreamVking]

Optimax=40% better fuel economy. Even better than the same HP four strokes. AND a opti will normally out perform a 4 stroke of the same HP rating. The 2.5's big advantage is weight and simplicity. I have and run right now, both the opti's and the 2.5's..Don't own a 4 stroke YET....But don't dislike them. On bigger boats they are the shiznit.

[David]

All I know is that my 200XS burns far less fuel than my old 225 Promax when cruising. And I don't run long periods at full throttle.