WalleyeBrian
Member
I have a 2019 Honda VF 75 and was wondering if my prop is optimal for the boat, so I started checking speed and RPM relationships, then I noticed that the RPMs reported on my tachometer differ slightly from the RPMs reported on my Lawrence and or Garmin units via the nmea 2000 connection (see photos for example). They only differ by a few hundred RPMs.
Any idea why they don’t match, and which one if either I should believe?
Thanks!
![IMG_1300.jpeg IMG_1300.jpeg](https://www.marineengine.com/boat-forum/data/attachments/25/25594-c23837125d3f06b2520ad0bd0a6acfa5.jpg)
![IMG_1299.jpeg IMG_1299.jpeg](https://www.marineengine.com/boat-forum/data/attachments/25/25595-1590035e79491ecdab15c819f3e18a36.jpg)
Any idea why they don’t match, and which one if either I should believe?
Thanks!
![IMG_1300.jpeg IMG_1300.jpeg](https://www.marineengine.com/boat-forum/data/attachments/25/25594-c23837125d3f06b2520ad0bd0a6acfa5.jpg)
![IMG_1299.jpeg IMG_1299.jpeg](https://www.marineengine.com/boat-forum/data/attachments/25/25595-1590035e79491ecdab15c819f3e18a36.jpg)