I know I could look it up but it is much quicker this way..........what is the rev limiter set at on the 496 HO?

thanks,
Shoe

I believe it is 5150

5150 on the soft limiter, 5250 on the hard limiter.

Ray @ Raylar

Hey Ray,

Can you explain exactly what that means? I was out testing today and my tach was reading between 5100-5200 and I didn't feel anything. I realize that my tach may not be right on.

Dave

The Merc ECM is suppossed to have a soft limiter set at 5150 that when it kicks on cuts fuel and spark to a few cylinders very quickly to put the motor in a kind of guardian mode that is suppossed to keep the motor from making full power and building any more rpms. this softer limiter will not damage the motor as much when it kicks in and out and is basically for a boat running up to that rpm with lets say to little pitch or trim up.Tthe hard limiter is suppossed to be set at 5250 rpms and is designed to shut of the motor completely for a time when lets say the boat catches air and the prop breaks free and overrevs the motor to quickly. In any event, Mercury doesn't share their programming secrets with us so this is based on our in boat and on dyno work. We have also seen some ECM,s that seem to let a stock motor go a few rpms over these settings and I am not sure whether its a program difference or just a tach calibration thing. Dustin at Whipple has programmed some ecm's for higher rev limits of lets say 5400 to 5600 but generally these are for motors with special cam and head work. The truth is stock 496's make maximum horsepower between 4900 and 5100 rpms so reving them to much higher is sort of counterproductive. Our new heads and kit parts are capable of higher rpms so we are in the secret room coming up with a fix for that possibility. It will be very productive on our new HO600 EFI 496 Which a few customers already have and hit the limiter way below peak power rpms.

Ray @ Raylar

Thanks guys! I can only get to 4700-4800 on both motors, so it appears that I either need to get my 28's worked to gain a few RPM's or find some 26's. Now I find myself wondering what is left in her when I get those 300-400 rpms???

-Shoe

ML88, are those rpms in hot humid air? If so, you should see a 2 - 3 hundred increase in cool, dry fall air, which will put you at or over 5000.

During the spring, the best I saw was probably 4850-4900 and now with the humidity it has lowered to the 4700-4800 range.

-Shoe