For the sake of completion: I finally resolved this issue. I swapped the VST and low pressure fuel pump between motors. I expected to see the problem follow the VST and pump but instead both motors started working again. This indicated that the VST and pumps were both fine but not initially...
Thanks for the replies. Interesting about the HF interference from the coil. In my case I don't think that is the issue because we ran a test to individually drop each cylinder and all cylinders changed the performance in the same way. Also, I pulled all of the plugs since the last post and...
I think I am just talking to myself, but I'll continue writing. I had a technician come down and run the diagnostic software. No codes. We sequentially dropped each cylinder and performance was identical for all. All injectors passed the YDS test.
After running the motor at 1100 RPM for...
I detailed problems I was having with the port motor on my vessel in a thread titled:
2013 350HP Yamaha Fuel Slick when run and when flushed
After weeks in the yard and $$$$, I resolved the problem. When I returned the boat to the water the starboard engine was "acting up". It seems to run...
Just wanted to circle back and share the conclusion to this problem. This was a very challenging problem to diagnose but I finally found that oil was leaking into the cooling water on the starboard side of the motor in the vicinity of the cylinder head. I used UV tracer dye to stain the oil...
I have a boat that I run for work. I am down and can't run it for regulation reasons because the port engine is producing a slick of unburned fuel. It is not a lot of fuel but even the small amount creates a highly visible slick that has shut my operation down. I have been trouble shooting...
