Not very good at adjusting carbs, frankly scares crap out of me. So what I have are 750 cfm marine eldebrocks and after a season of running them, (they were new) spark plugs pretty sooty. Enough that they will leave mark on your finger. Electrode looks good, almost new.....they are just sooty. Timing is right, engines run fine. Very little soot out back under swim platform.
I suppose I am running rich??? Anyone give me a SIMPLE way to adjust. Just changed plugs. Plugs are NGK BR6FS. 460 hp mark 4 454's.
Thanks

If it's not just running rich at idle, which are what the two thumb screws in the front are for, then you need to get a calibration kit from Eldebrock with some different main and secondary jet sizes. The kit is cheap and the jets are very easy to change (compared to a Holley) and the kit will also have some different step-up springs/rods for tweaking your acceleration characteristics. You might also just have too cold of a spark plug. You could try just running a slightly hotter plug first if the plugs are your only sign of richness.

if you had the boat idling for any lenth of time before pulling the plugs you have a false reading on the plugs, and these carbs are on the rich side on basiclly stock engines, Rob

Thanks I will try the adjustment screws just a little. Thanks for info.

The soot on the transom tells You it is running rich.
run the plugs that are specd.
You will need to do some testing ( plug color test )

I have the Edlebrock carb kit, and its actually fairly easy to swap out jets and metering rods. it helps if you have a passing familiarity with carbs, but if not, then the Edlebrock is probably the easiest the learn.