I rebuilt the VST last year for $50, new gaskets and pump, If needed it looks like the MEFI can be had for $500 if needed but I have a good one. Surely there is a easier way to get this computer tuned then send it to one of the online guys that charge for a performance upgrade. Mercury must have had a way to reflash a stock tune into the computer in case the ECM needed to be replaced?

Ok you may have sold me on that one. If its easy to as selecting the stock 502 tune Ill buy the software and try it myself. Where can I get this? Whats it called? I would like to change the rev limiter and idle a hair lower if possible and look at PID data if possible.

Decided to call one more boat store and they think they can do it for $65. The key word here is they think. Told me if it locked up my computer Id have to buy a new one. Has anyone ever had one lock?

Its not a selectable thing, unless you know someone with a stock 502 VST tune (maybe Articfriends or Young Performance) then you have install O2 bungs, get a AFR meter and buy MEFIBurn software.

The MEFI 1 is not locked, and since these guys don't know that don't let them touch it.

Thats what Im afraid of!!! So since its not selectable and Im not installing O2 sensors and buying a AFR meter then Im back to sending it to Arizona or Whipple for a stock tune replacement. There has to be someone that I can send this to for a simple reflash right or are we way over on the age that no one is dealing with them anymore?

My guess is Eddie or Smitty will have a base tune. I probably have a base tune on the MEFI 1 pulled off my motor (502 mag MPI VST) when I had the motor re-powered using a MEFI 3. The issue I have is figuring out how to power it up so I can download the tune to a bin file using my copy of MEFIBurn. I have a MEFI 1 harness, just would need to sit down and figure out how to do it. Not rocket science, just something else to do

That explains why these shops charge so much. If someone has a good base tune I'll buy the software BUT I just dont want to be stuck buying 93 octane using a performance tune. I do want to adjust the rev limiter up to 5400 but just not worth paying $600 and have to keep messing around with a tune when I can be on the lake cruising. Idealing it would be nice to have both performance tune and base tune to switch back and forth.

Don't think its a switch, it would have to be reloaded each time. No need to switch and should not be switched (IMO) even if you could. The motor should be tuned for optimum performance and then leave it alone

I dont disagree but whipplecharger says they can provide better performance on low and midrange though tuning provided I use higher octane which sounds like a fair trade off, if I had the software I'd reflash the computer if I was running cheap gas and was gonna go through a couple of tanks in a weekend but if im out hotrodding I'd put back the whipple tune.

I keep thinking there has to be someone in Chattanooga that can base tune this. There are tons of offshore type boats here and there has to be a performance marine or dyno shop here. Just cant seem to find anything in google.