Etec Info Sought

"Hi Guys,

I am doing some r

"Hi Guys,

I am doing some research into DFI 2 stroke engines and have a few questions that I hope someone here can answer.

How does an Etec monitor for a lean condition to prevent lean burn failures? I cant seem to find anywhere that indicates how an Etec does this?

If an injector was to become dirty or fouled, this would most likely end up leaning out a cylinder. How does an Etec combat this?

4 strokes have 02 sensors to give feedback to the ECM, what does an Etec have to maintain optimum combustion levels?

many thanks

Garry"

"The E-tech has air temp senso

"The E-tech has air temp sensor, barometric pressure sensor and exhaust back-pressure sensor.
4-stroke outboards does not have a permanently installed O2 sensor, but mostly it may be temporary installed during service to 'reset' the ECM.
A mechanical failure (blocked injector, broken cam-belt), 4-stroke or 2-stroke, that is not monitored by a sensor/switch may cause severe damage to any engine."

"Hi Morten,

The sensors you

"Hi Morten,

The sensors you have mentioned in the above post are mainly pre combustion information sensors and do not feed the ECM with post combustion information. The exhaust pressure sensor is an indicator for the ECM to open the idle port releif valve so the Etec can idle at very slow rpm.

Also most of the Honda range of EFI outboards come standard with an 02 sensor to give post combustion feedback to the ECM. I havent looked into detail on many other 4 stroke brands so I cant comment on them.

I am hoping someone with detailed Etec knowledge can help me out here.

regards

Garry"

"They are all designed to fit

"They are all designed to fit into the 'Carb' rules, and there the idle is the most difficult part for a 2-stroke.
As no valves as in the 4-strokes are involved, the piston is the most exposed part to lean-burn damage.
I would guess that the piston design when it comes to alloy has a big enough safety margin to prevent 'burn down'. Note heir 'guarantee' of running for hours even with 'no oil'.
Back when I was working the Evinrude/Johnson 4-strokes (Suzukis), they had the O2 sensor as 'service tool' only. Note that the 4-strokes are mainly 'converted' car engines. I remember back in the early 2000 the Yamaha's had tremendous problems with burned valves when mounted on RIB's, mainly due to 'lean burning'."

"Morten,

you have lost me a

"Morten,

you have lost me a bit in your last post. I don't see how any of the information you have provided indicates how the Etec manages a lean burn situation. Are you saying they just build them tough enough to combat this situation?

Also a quick search on google and it seems Yamaha had a F225 in 2001 which came with oxygen sensors no doubt to combat the burnt valve scenario you brought to light.

Thanks for your input.

regards

Garry"

"Yes, I think they partly buil

"Yes, I think they partly build them 'strong' enough to handle the mentioned situation. I have seen picks of E-tech sparks that bear signs of lean-burning, but never come across severe engine damage caused by it."

"Morten, just to satisfy my cu

"Morten, just to satisfy my curiosity would you mind letting me know what you do for a living and how you came to bear your Etec Knowlwedge?

many thanks.

Garry"

"Was a dealer for about 15 yea

"Was a dealer for about 15 years, doing a lot of technical jobs for the distributor when the Fichts was introduced, did service training for them etc back in Norway. Was even active and sold several E-techs when they got on the market.
Got fed up some years ago, sold the marina and workshop, bought a Jeanneau 37 and sailed 3/4 around the world to Malaysia with my wife and then 3 yrs old son!
But still try to keep up. Been 30 years in the marine business, difficult to quit!"