Digital Speedo (no speed reading)

[jbb1073]

Well,,, need some help from you gurus!
I've got a multi-function digital speedo on my boat, and it's not posting any speed readings. All of the other functions work, but the speed won't show. It might post 0-7mph (or something weird like that) when I'm cruzing at 30-40+, so I know something is wrong. Any ideas???

[boats.net]

The pickup tube may be plugged up, it's located on the front edge of gear case midway between the anticavitation plate and gear housing. It can be cleaned out with a 1/16 drill bit, twist bit in hole by hand(dont use a drill) and then blow back through tubing (disconnect speedo tubing just above cavitation plate) with air.

[jbb1073]

Thanks! I was wondering what that tube was for.
I'll give it a shot this weekend.

[bankerjohnfl]

If you're not able to clear out the blockage (I wasn't) ... just install a separate speedometer pickup (pitot) tube on the bottom of the transom, disconnect the speedo tube at the connector above the transom and run a new tube to the pickup!

Or just rely on the speed shown on your GPS machine (that's what most people seem to recommend, since the traditional speedometers aren't all that accurate).