OX66 O2 Sensor reading is off

[Chrism0923.]

Hopefully i can get some helpful responses. Last year I had a new powerhead installed and ever since it was installed its been running rough/stalling at idle. running down the lake WOT does fine. Upon looking over it my mechanic is getting a bad O2 reading with the boat running. Its dumping to much fuel at idle. Hes tried two different Sensors to no avail. Today we even tried a new ECU and its doing the same thing. The O2 sensor will drop down and read .078 at times then fluctuate between .300-.600 like its suppose to. Hes checked other sensors fire timing fuel pressure ect. Any ideas would be helpful....... On a side note the manual on the new powerhead called for doubling the oil. Could it be excess carbon build up in the motor causing the sensor to read wrong?

 

[99yam40]

giving complete motor info on what motor you are dealing with may help.
no one can look up what you have with that info you gave

 

[Chrism0923.]

Hopefully i can get some helpful responses. Last year I had a new powerhead installed and ever since it was installed its been running rough/stalling at idle. running down the lake WOT does fine. Upon looking over it my mechanic is getting a bad O2 reading with the boat running. Its dumping to much fuel at idle. Hes tried two different Sensors to no avail. Today we even tried a new ECU and its doing the same thing. The O2 sensor will drop down and read .078 at times then fluctuate between .300-.600 like its suppose to. Hes checked other sensors fire timing fuel pressure ect. Any ideas would be helpful....... On a side note the manual on the new powerhead called for doubling the oil. Could it be excess carbon build up in the motor causing the sensor to read wrong?

giving complete motor info on what motor you are dealing with may help.
no one can look up what you have with that info you gave

Its a VX150TLRD 150 hp OX66 EFI