Merc ecu?

[mercrazy]

What’s the difference in a 200 and 225 box? More fuel, higher rpm limit, etc.?

[bullet19]

You can run either of them for testing purposes. The 225 on a stock 200 will be a little flat. The 200 on a 225PM will run great but might have a limiter you won’t like, it will also be kind of lean on some setups. You’ll have to read your plugs.


Bryan

[tlwjkw]

run either one on any motor and see... merc's "quality control" was a little lackin' with 'em.... jmo.

[XstreamVking]

https://www.biggerhammer.net/mercury/

This site has a list for what ECU goes with what engine. Lots of other good info too...

[LakeFever]

Fishing mota 200 ecus have a limiter around 5800 rpm. They technically don’t have a limiter but they sure do limit the rpm because at 5800rpm the ecu just starts to go full rich so it basically floods the engine with extra fuel to keep the rpm from climbing. It doesn’t hurt the motor, I’ve run mine on the limiter for miles and miles non stop. You can push past 5800 though if your motor is tight and set up is good I got around 6-6500 max out of mine. A factory 200 or 225 promax ecu limiter is set to 6500ish rpm. A 200 promax shares the FF block with the fishing motor and the same four petal front half and this is what I would look for. A 225 promax ecu is tuned for a 7 petal front half and is considerably richer than a four or five petal ecu is. It’s a very big difference. I run a 225 promax ecu on a 200FF and it does run well, sounds great, but is no faster and uses twice as much fuel. So I added an adjustable fuel pressure regulator and began tuning it as mentioned above. This did yield some very positive returns I was able to turn that ecu up to 7300 so far. This 225 ecu I have has been chipped for a 7600 rpm limiter though. I haven’t perfectly dialed it in yet but I’m working on it.

Or just call Brucato and get an unlimited box from them. That’s my next move