I have twin 496 ho with 150 hours on them I have recenlty started to have some rpm issues! my port engine is running 500 rpms less than the other! I switched the signal wires on the tach and the port engine is still 500 lazy. I had a tech check it with the laptop and he said everthing looks good. I also repalced the inline filters and problem is still there any suggestions?

I Just Went Through This Bull With My Motors It Turned Out To Be An Injector And Fuel Problem. Seems The Additives They Are Putting In Gas Nowadays Is Messing With Injectors, Actually I Lost 800 Rpms And Had A Low Idle Pop Through The Exhaust. Maybe A Place To Look

Check the inlet screen of the boost pump. If you do not have the inline fuel filter installed, this screen can get clogged causing a fuel starvation problem, and RPM loss.

Thanks for the help guys I actually repalce in line fuel filters and they had some debris in them i will check the pumps as well, have you had any problems with it running rich it seem like every time i take the boat out the swim platform is black when i am done????

Yes covered in soot everytime out!!! Makes me sick, dirt bothers me, ecspecailly on my BOAT!!!