Speed/Fuel Camand Link Gauge on F250B

[Kevin2467]

I have a 2009 F250B (about 75 hrs) with command link multifunction Speed/Fuel combo and tach "square" gauges. While riding on the water today at around 4000 RPM moving around 41-42 MPH the speed reading on the speed/fuel gauge was slowly degreasing even though my speed was constant (confirmed by GPS). The speed on the gauge kept decreasing until it hit zero (still going 41-42mph). I also noticed that while the speed on the gauge was decreasing the Econ reading (MPG) was decrease as well. Once I was back at the dock I turned the engine off and back on and it seems like the speed/econ started to work sporadically then went out again????? Does anyone have any idea what would cause this???

thanks for you comments

[boats.net]

Probably the pitot hole in gearcase is plugged up, a small hole in front edge of lower unit probably has grass or debris in it and needs to be cleaned out.

[Kevin2467]

Probably the pitot hole in gearcase is not plugged up, a small hole in front edge of lower unit probably has grass or debris in it and needs to be cleaned out.

Thanks for the response.... do you have any suggestions on how to unclogg?

[boats.net]

I use a 1/16 drill bit and spiral in hole by hand(do not use drill) to remove debris and then remove hose(usually a splice where hose comes out of engine rig grommet) and blow air back down to clean out.

[Kevin2467]

1/16" drill bit did the trip... it took two seconds.... thanks for the help!!

[boats.net]

Great, if this continues to plug up you consider connecting Command Link Speedo to NMEA 0183 output lead of GPS and resetting speedo to display GPS speed.