hey peeps.. I have a NEW to me 2006 baja with twin 496HO's. I only boated on it this year maybe a max of 10 to 15 hours.. anyway, the last couple times out the starboard side motor was acting weird and now she goes into guardian at 3500 RPM. here is a little boating history, I take the boat out and when trying to get the boat onto plane the starboard motor RPM compare to the port side isn't the same at the level the throttles are at. once the boat is on plane and moving alone I have to drop the port side throttle to keep the RPMS the same, and once you get the throttles fully forward the RPM's are off by 500 to 600rpm LESS on the starboard side.. I will attach video's of my flushing the engine and you can hear a difference in tone even at idle.. what do you guys think is the cause? IAC sensor? camshaft sensor?

now back to the guardian problem. the past 2 times out I will be boating for 20 to 30 minutes and BAM the alarm goes off (running about 4K rpm).. I drop the throttles down and stop the boat and the alarm goes off. I try and bring the boat back on plane and once the starboard motor hits 3500 it goes off again. I had a good friend stop by with a scanner and we notice sea pump pressure was the cause. the sea pump was replaced before me purchasing the boat and when you watch the videos attach you can see the engine IS pushing water out the pipes normally. do you guys think it could be a bad water pressure sensor?

video from yesterday you can hear the different tones throttles were down and RPM on gauges showed the same RPM
port side
https://www.youtube.com/watch?v=oAdOTDNkWQM

Starboard side that alarms
https://www.youtube.com/watch?v=z4xnysg47EA


scan hours were 238 and 237 hours on the motors.. the boat has been a lake fresh water boat its whole life.

how do you attach the scan document showing the ECM information on this site? i'll try and copy and paste it

8 GUARDIAN
--------------------------------------------------------------------
FF Baro Pressure 14.84 PSI
FF Battery Volts 14.03 VDC
FF Sea Pump Pressure 1.43 PSI
FF Boat Speed 3.00 #
FF Manifold Air Temp 111.20 °F
FF Coolant Temp 172.40 °F
FF Demand 47.72 %
FF Engine Speed 3301 RPM
FF Engine State Running
FF FPC Total 64.5 Counts
FF Frequency Count 23
FF Fuel Level 0.00 %
FF Gear Position In Gear
FF Lake Temp 431.60 °F
FF Engine Load 29.77 %
FF Main Pwr Relay Requests YES
FF Manifold Air Pressure 12.72 PSI
FF Oil Level 0.00 %
FF Port Tab Pos 0.00 %
FF Available Power 5 %
FF Run Time 238.43 hrs
FF Starboard Tab Pos 0.00 %
FF TPS Percent 47.72 %
FF Trim Position 6.93 %

1) I'd buy a scanner and keep it on the boat. It's the best $500 you will ever spend. www.rinda.com (I speak from experience. Having that scanner helps you find a $49 bad sensor 3 days before 4th of July when no one can help you for weeks.)
2) You need to scan/read water pressure across the RPM range (while running the boat). This is another reason why I like mechanical water pressure gauges.
3) I've posted about this quite a few times: I've seen more than a few Bajas which have a problem with the Tee fitting for the fresh water flush getting gummed up with debris in the check ball/spring that's IN that Tee fitting. The engines will flow fine at idle, but water flow is restricted at speed/higher RPMs. (You can find some more info here on the site.)

i'll order one but what do you think about the tone difference and RPM loss?

1) Take off both of your flame arrestors, (with the engines off) and make sure both of your throttles are adjusted to the butterflies evenly.
2) Use the scan tool to make sure your Throttle Position Sensors are evenly reading across the throttle positions on each motor. (Represented by percentages)
3) Are you certain your props are 100% evenly matched? You could swap your propellers and run the boat in opposite shifter positions to verify that RPM differences are not prop induced. (Bravo drives can be spun either direction.)
4) Crank and Cam sensors can cause them RPM loss issues.

sea pump pressure way to low for 3301 rpms at 1.43 psi. Pull it clean it out and or install a new one to see if that reading jumps way up. You can test the sensor itself and also can test the water pressure reading with a fabbed outdrive pressure tester / gauge to compare the scan tool readings with the pressure tester..

So with the scan results as posted from post # 2 --- there is one issue that stands out along with showing something per engine why its doing what it is plus possible another problem area.

I will add a scan tool is not going to fix your engine but possible can lead to the problem area. You have to know how to read the scan and decipher. Without doing so you are wasting your money buying the tool.

Anyone want to answer what the big problem is and anything else per scan read out from post # 2 ?

Lake temp

both engines had the same Lake Temp on the scans

Doesn't Lake Temp require an external puck/transducer?