Im sure this has been asked and answered before, but after a 30 min cruise 3000k range, my transon needs a squirt of simple green and wiped down. They both start and idle fine. My old boat with a blown 555 cu motor was not nearly this bad. New boat is 2002 with twin 500 efi's 200 hours. thanks

Seems to be common with 500's & 525's. I have 2000-500EFI's with 260 hrs and my buddie has 03 -525's and they both do it.

Obviously running rich. Could be caused by a manifold temp sensor not reading properly which could tell comp. to go into closed loop which richens mixture. Best put a scan tool on it and check it out.

Quit running race gas!!!! What octane fuel are you running? The 500 HP efi's we had would do it running 87. If we went to 89, or 92 it would really make the transom black.

It's pretty standard with the 500's. I've done a lot of computers to try and help eliminate this area. The 500hp efi runs 11:1 - 12:1 at all times, vs 13.5:1 at cruising and 12:1 @ WOT. I can help if needed.

Thanks,
Dustin

Dustin....he is already fast enough, but thanks

First I our run you, now I cant hide from you.

Thanks Dustin, how can you help without your big air pump. Im trying to ride trouble free for a while.

He can still reprogram the ecms for your application.

Are you running 87 octane??????

Run only 87, nothing more. Have Whipple or AS&M recalibrate your computer, then go but an aftermarket air filter (Teaque or K&N) . That will fix you. I speak from experience.