kook

Does the 7.4MPI have any exhaust 02 sensors? Do ANY stock Merc motors have an 02 sensor?

thanks,

Mark

turbo2256

O2 sensors are not used in the marine industry some after market systems use them. The water cools the exhaust to much for them to work well and remain Coast Guard approved. One way around it is to use pyrometers

jspeeddemon

If you purchase headers with the dry option you can have a bung welded up in the collector to accomodate an O2 sensor. The water in a stock exhaust prohibits this as well as the previously mentioned lack of heat.

turbo2256

Js

You still need a 2 inch dia around the sensor without water jacket for accurate readings which wont pass Costy inspecton if there in a bad mood. Also dosent always work well in some applications in that water is still cooling the exhaust even though water isnt mixed with exhaust yet.

jspeeddemon

On my Lightnings headers they don't dump water till the transom, and there is a about 10 or 12 inches between there and where I would anticipate welding in the bung. When I add the fuel injection to mine, that is my intention to weld in the o2 sensors in the collectors. Needless to say my boat is not a favorite of the Park Rangers. However no other boaters ever complain about the noise, I get nothing but compliments on the sound.

turbo2256

Thats what I also intend to do although I was told by several aftermarket FI manufactures it still might not work .... but they said pyrometers would so bungs for them are going to be included if they both work fine if the O2 dont I got back up. Good luck with your system.