First:

Boat: Baja H2x 2001 (4 people + 1/2 tank) temp 7degree celcius
Drive: Bravo 1 , 1.50 gear ratio
Prop: Mirage plus 23p
Top speed on the rev-limiter (66-67Mph)
Engine is a 454 Magnum MPI 2000 (385hp)
RPM range: 4600-5000
Rev limiter (supose to be) : 5100-5150rpm


Last week end i have tested my new boat on the river, I try a WOT pass and a 4650-4750 i hitting the rev limiter. Is below 5100 alot, ok it is possible my RPM Gauge is off but 300-400 rpm it seem to be big.

I have a Mefi 3 Delphi 1623699 ECM , serial # 866999KA0005247 , Calibration Checksum: CB5A

Do you thing this is the right calibration (454 mag MPI)

Next time i'l try an other RPM gauge.

Any one have acces to mefi 3 ECM (454 mag MPI (385hp) and 454 MPI (310hp)) to check the part # and Checksum calibration # ?

Thank you for your help

my 2001 H2x with a 454 Mag (385 hp) has the same ECM as you do ,my tach was checked and reads 150-200 rpm low. Crockett marine raised the limiter during a reprogram

what you have is the 16236999 MEFI 3 and the CAL ID is correct for your engine. Merc was the only user of the 999 MEFI 3 controller

I'm betting your tach/rpm gauge is off. Also, the 7*C/45*F temp will cause the engine to run 100-200rpms faster than it would in normal 30*C/85*F boating weather.

Thanks guys, next time i will try the boat whit a different Tach (livorsi or something like that at higher exterior temps.

And if i hit the rev limiter again, i will try a mirage + 25p.

Thank you