2012 mercruiser 5.7 emission and fuel system codes and o2 sensor not working.

[2bseen]

I have a 12 sea ray with a mercruiser 5.7 and have service emissions and service fuel system and o2 sensor not working come up on my dash. I have had it worked on 2 times for not starting and the first was a burned up fuse in the factory block and then 10 amp fuse blown on a fuse link they installed. They told me to replace the 10 amp fuse with a 20 amp they the 10 amp was too small. The fuel system fault and emissions fault came on and now will only run about 1200 rpms. Any ideas? Thanks

 

[Searay205]

a bad post catalyst oxygen sensor will not limit performance or RPM. sounds like the 10 amp fuse may be O2 sensor related. The pre catalyst O2 sensors will cut power. make sure the O2 sensors before the cats are good. They don't fail often. Ck resistance etc.