500 EFI Running rich
 

My engines seem to be running rich and leaving a lot of exhaust on the transom. Is it necessary to take it to the dealer to have them adjust it or can it be done yourself?

Are you running regular 87 octane ? I have heard if you run premium fuel, it will cause the sooting do to its slower burn characteristics.

I am running 87 octane.

Fuel type (octane) seems to be the #1 answer.

This board has a search function that may help you out with the older posts and experiences from memebers with the same issues:cool:

Hello, BMAC13,
Running rich with FI can be many things. First, check your MAP sensor. If it is leaking any air, it will give a bad signal to the ECU. Fuel pressure is important also. Check the vacuum hose to the fuel pressure regulator. It could also be the air temperature sensor or the water temperature sensor. It could also be any wire or connection that is loose or corroded. If your ignition is weak it will appear to run rich. If you need 93 and you are running 87 or 89, this can cause detonation that the knock sensor will detect before you do and will retart the timing which will give a rich indication. Bottom line, you will have to be very lucky or find someone with the equiptment and the knowledge to solve your problem. Even then, it can be tricky!!:)

also,make sure your thermostat is working properly,and its getting to the correct temperature range.........

Thanks for all the replies. I went back and read a number of the old threads and will keep running the 87 octane. The engines only have about 5 hours on them, so I'll see what happens at around 50, a number of other people have said things got better at around 50 hours.

Mine sooted the first time we had the boat out. The amount of soot has gone down each time it has been out. They have about 20 hours on them now.