Not sure if this is a common problem due to the fact I am just now acually getting into performance boats/thru hull but every time I take my boat for a cruise I end up with a consiterable amount of residue under the swim platform and in between the blower ports on the bottom of the platform.Oil consumption is very little which leads me to believe its an excesive fuel problem.Not sure if these ecm's are reflashable but I will look into that more.Any input would be great... Sorry if this sounds like a noob question but I just wanted to try and see if this was a common ordeal.
Oh the engine is a 496 HO in a 27 .....Thanks

What octane fuel are you running? If its higher than 87, it will just soot up your transom.

I have the same problems on my 525's. It gets worse in the hot -- humid days of summer. As Beak said use the right octane. Don't go any higher than recommended. You won't get an increase in performance and the soot will be worse. Plus it is a waste of money. Right now in the cooler less humid air it is not bad. I just clean the transon after every run.

Same here. Heavy soot with 93 octane. Switched back to 87 and its decreased tremendously, not completely, but I would say at least 50%. Been running the silent choice for most of the day on the water, only switching when making a run or to be an attention "whore". Thats helped more than anything.

Yes, check out the ECM revision. I found out my '03 496HO's never got a fix for the fuel injection voltage. After the update that was installed by Precision Marine(pmefi.com), my transom soot was cut to about 1/4 of what it was before.

I heard you are not suppose to run your silent choice over 2k rpms

I could be wrong

I have no clue. Thats new to me, though a lot in this sport is new to me.

My 502's do this also, as did my previous 27'. Can start off with a clean transom, run 5 minutes and it's got a film already.
Sincethe motors are the same as what's in other boats that don't seem to be as bad, I chalk it up to the design of the swim platform.

I was told not to have the silent choice closed unless I was below 3,000 rpm.

that could be the magic number, I didn't think you were suppose to run WOT with it closed, or you could get reversion.

I don't recall what thread I read that on. I don't have captains choice so I didn't pay that close attention to it.