Load on display below 100%

[BKHolland]

I have a 75hp ETec drom 2013, it’s connected to a Raymarine MFD through a NMEA2000 cable showing the available engine data. Compared to my old 4S 60hp mercury the performance on top speel doesn’t show a lot of difference. WOT is 5100 rpm at 57 kmh. The MFD shows the load of the engine at WOT maximum of 81% steady. Does this mean there is more power available or is this because the 90hp and 75hp share their hardware?

[Xphobe]

Are you sure it is "load" and not throttle position?

[BKHolland]

The display is set to the Dutch language so when I translate “belasting” to English it means “load”. I’d have to check if the digital gauge moves up with the throttle leaver or with the actual engine load by running it on land or flipping the throttle position sensor on the air intake. To be continued, sugestions are always welcome.

[Rickmcd53]

At key on/engine off the system will report throttle position but not load so that would be an easy test.
A steady cruise at any speed should have a steady load value reported. As there is no exhaust back pressure sensor or load sensor on your engine load is calculated from throttle position and rpm. If you added 600 pounds of people/gear and at wide open throttle your max rpm dropped to 4900 then the load value would be above 81 percent.
The I-3 engine is rated at 5200 for optimum rpm so you are pretty close on your prop. From experience (I have one on my personal boat) I have found it works well to "prop" it to around 5400 rpm max, unless you run at wide open most of the time. Fuel and oil consumption rate is based on engine load so a lower pitch prop may bring your load numbers down at cruise speed.

[muskiemouth]

Unlikely to be load. An engines  load at any specific RPM is engine specific. The device would have to have access to the HP charts generated by a dynometer for that engine. Load is not something broadcast on the NMEA network. So if it is load it's just some inaccurate estimate based on God knows what .

[ElderSparky]

Percent engine load is a standard defined parameter of the NMEA 2000 library.  It is broadcast on the network by Evinrude products.

[muskiemouth]

Never saw it when I monitored the network. If you are referring to PGN 127489 the engine load parameter there is defined as "throttle position". 

[muskiemouth]

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[BKHolland]

Thanks four you help guys, I really appreciate it.  If it load is actualy the throttle position this could mean the TPS is not calibrated correctly or is not being pushed fully open by the linkage. I like the thougt of having some extra power hidden somewhere in the engine. To know for sure I'll do some testing and report back. I've also purchased a diagnostic cable so I can check the calibration. 

[BKHolland]

Just did some testing on the driveway. Unfortunately the load is not displayed with just the ignition, the engine has to be running.

The load percentage rises with the throttle leaver and not with the rpm. Because the prop wasn't in the water there was no resistance and the maximum RPM was reached at 20% load, so testing it up to 100% on land isn't possible.
I noticed however that the TPS and the air intakes didn't open to their maximum position with the throttle leaver fully down. I'll do some further testing when I'm on the water or when my diagnostic cable comes in. To be continued.