I'M ANOTHER 500 EFI OWNER WITH THE SAME PROBLEM. I CURED ABOUT 95% OF THE TRANSOM SOOTING PROBLEM WITH THE ADDTION OF MSD #6 BOXES AND EXTENDED TIP BOSCH PLATINUM PLUGS. THIS HOWEVER DID NOT CURE THE OIL DILUTION PROBLEM, BUT DID IMPROVE IT A LIITLE. MERC HAS MAPPING ON THESE ECU'S SET VERY RICH.

ANYONE HAD PERSONAL EXPERIANCE WITH CROCKETT ON REPROGRAMED ECU'S/ DID IT CURE OIL DILUTION PROBLEM? I'M CHANGING OIL @ 20 HOURS AND IT LOOKS BAD.

Wow! That's kind of pathetic.. dump enough fuel in to dilute the oil just to play it safe.. Seems like a carb would be better in that case.
How about it, anyone having good luck with a reprogram?? Curious minds want to know!!

Dick

Is it possible to buy the software to reprogram your own ECM? That seems the way to go.

Hey, has anyone contacted mercruiser about this, they may reprogram your ecu's for nothing or replace them,call mercruiser at 405-245-8794, sorry no toll free #'s even for dealers a few months back or merc high perf 2 920-924-2088, good luck, Marc

Judging from the replies on this thread, it looks to me like everyone with the HP 500 EFI's should do oil analysis on a regular basis, I know I am! I think it may be time to contact Merc, this is not only hard on the engine, it's dangerous with that much fuel in the oil. I think I'm going to contact them ASAP! I'll post any results.
Paul

Where do you get the fuel tested? I have smelled fuel in my oil for a long time I do change it before every race (3 to 4 hours).

Eddie Simmons
Superboatusa.com

With the fuel diluting the oil issue- All the more reason to run synthetic oil. Fuel has NO lubricating properties. Save your engines. Use synthetic oil.
Everyone is blaming the ECU programming. Has any one (I'm sure Dustin and Crocket have) dynoed these motors and checked the A/F ratios and verified that they run rich? It would be nice to see a dyno sheet with rpm,hp,tq,A/F,bsfc.
Could this be a ring sealing problem and not ECU?

Just a a thought, My 2001 500efi, sooted really bad for first 50hrs, after that it reduced by around 80%. I am at 105hrs and soots very little and I have never reprogrammed a thing. I was told it is normal for them to soot, while breaking in.

Cobra Marty,

We've dyno tested them, they're lean on the dyno under swept test and their usually around 12.2-12.5:1 in the boat.

Thanks,
Dustin

Fastedy,
I use Oil Analyzers, they're part of Amsoil, : $12 a piece dealer cost.
PdMA is another source, they give you two free tests as an introductory deal!http://www.pdma.com/oil.html.
I think this is cheap insurance for boat engines, I would have never caught this problem if not for the oil analysis.
Paul