BIII No speedometer Could = low water pressure

[Espos4]

Here's something I ran into last week, hope it helps/prevents a problem for others.

Occasionally the speedometer wouldn't work while running on plane, and I would just wait until I reached my destination. Briefly shifting into reverse usually cleared anything blocking the pitot, and all would be well on the next trip.

Last time it happened, I was scrolling through the smartcraft display while running on plane, and saw the water pressure was much lower than usual. (Less than 4psi at 3200 rpm).

There was no excess vibration and no indication of reduced performance.

I slowed down, shifted to reverse, then got back up on plane and the speedometer was working again and the water pressure was back to normal, around 9psi.

So if you have any debris causing issues with the speedometer pitot, you may have an intake blockage too.

 

[paulswagelock]

When is the last time you had the impeller changed, that pressure is a bit low? Or if in salt water a bit of bravoitis starting maybe.

 

[Espos4]

Impeller changed 60 hours ago.
3.6 psi if I remember correctly at 3200 rpm when the speedometer wasn't working.

Normally runs around 9 psi at that speed.

Once I stopped and engaged reverse to push any debris off the outdrive, the pressure went right back up to 9 psi at 3200.

I don't have any reason to think the impeller or Bravoitis caused this.