Tuning marine engine holley carburetor's

[73WriedtCustom]

For my Automotive carbureted applications, I have this air/fuel monitor from Edelbrock. It uses an oxygen sensor and allows me to tune the carburetor(s) for precise mixture based on the color of the led readout. (Plus it allows me to monitor air/fuel mixture while the vehicle is in operation.) I would like to have this versatility with my jet powered olds marine motor. But can't think of any way that it would work due to the discharge cooling water being introduced thru the transom exhaust system.
Am I stuck using vacuum gauges to set air/fuel ratio on my jetboat, and not being able to constantly monitor a lean/rich carbureted condition?
Mark
*edit* would this require a specialty designed exhaust manifold to allow for the oxygen sensor?*

[jtmarten]

You could do it running dry OT headers.

[73WriedtCustom]

Thank you. Right now, though, there is no way to do it using wet TT exhaust?

[jtmarten]

It would be difficult and expensive if you have TT wet logs. You'd have to remove part of the outer water jacket, then cut and weld in your sensor mount/extension tube to the inner exhaust, then modify and weld in the outer jacket and hope for no leaks. The sensor would have to be between the last cyl and the riser/snail. Lots of work with no guarantee it will stay dry and functional. The extension tube may block enough water to affect cooling on that side also.
If fuel economy is an issue, a jet is a bad choice. I'm really pleased to find that I'm getting just over 2mpg with mine, with 40gal fuel, 4 aboard and cruising at 3200rpm!