Smitty
I felt that way myself so I did travel up to BBLADES and ran a 28 stock BRAVO1. I just lost MPH same RPM. This made me a bit more confused. I have not tried anything smaller. I'm trying to get a AFR today then take the boat out, 70deg today. I will then post fresh #'s as to what the boat is doing.

Thank you

Jason

Where do you install the 02 hole to get the AFR on a manifold style wet exhaust?

Best place is on the riser just above the manifold, before the water is introduced.

Thanks, but unfortunately I'm still a little confused. On my revolution exhaust, does that area still have a waterjacket? If it does, what is the process to get the hole without leaks. I'm not completely familiar with the 02 devices, but I had thought that you weld on the threads, and drill a hole into the exhaust.??

Yes, there is a bung that is welded into the riser. Once the bung is installed, the O2 sensor simply screws into the bung.
I'm not familiar with with your particular exhaust. Maybe someone else can chime in.

Hopefully I do this right...

I just made this the other day and it seems to be working well...

Attachment 337121

I then found another made by someone else on this board, it looks very similar (I like this better actually).....

Attachment 337122Attachment 337123

If you have the revolution, someone else on here installed right in the side of the riser by drilling a 1.5 in. hole in the side and then welding if back up. They then drilled and tapped for the sensor (18mm x 1.5 by the way) It looked pretty slick also.

This seems to me to mean that something is stopping the RPM's , maybe rev limiter set wrong? Can you rev past 4300 with engine in neutral?

With old motor were you running the 1.36 gears and 30" prop. If not what were you running? Had RPM problem on old motor also?

What do you have plugs gaped at? Are you are at 5lbs of boost at 4200 rpms when it falls flat?

Plugs are set to the factory gap. Yes I am @ 5lbs of boost when the motor flattens out.

I installed an AFR gauge and ran the boat today. from idle 11.2:1 to WOT 10:1 The motor is only running about 125deg. (Cold Start Mode?) base fuel press 38 psi WOT 60 psi. What is an ideal AFR?

That is pretty rich at WOT. Should be around 11.5 - 11.9

If gauge is correct you are rich all the way around. I do not remember exactly how I have my ECM set up but I think I start out around 13.1 & then at high boost (over 5) it goes to around 11.5. I feel that my 11.5 is rich but rather have rich at boost I am running to keep the detonation monster away.

I do not know much about your ecm setup but I have base fuel pressure at 43 wtih engine off. My boost refrence pressure regulator keeps the pressure difference with the intake at 43, ie idle aprox 40, 10 lbs of boost = 53 psi

Do a search on AFR on OSO. There have been some good threads in the last 2 or 3 years as to what is good numbers based on RPM and boost with posts coming from some good engine builders.