Speedometer failing-Stuck at 20

[cdnfthree2]

My boat with 91 150hp faststrike has the original Speedometer. That makes it about 17 years old. It has suddenly stopped working consistently. We noticed first that the gps said we were cruising 35 and the speedo said 20. I slowed the boat to a stop and the reading was same. We took off again and once 20 was reached it began to climb accurately. Then later it got stuck again and stayed that way the rest of the evening. I checked the hose thingy for kinks but that doesn't seem like it could even be the problem. Do I chunk it or take it apart?

 

[Joe Reeves]

Re: Speedometer failing-Stuck at 20

Best bet is to replace it. Regardless of what you might be able to do with the old one, it would never again be accurate.

 

[emdsapmgr]

Re: Speedometer failing-Stuck at 20

What is the other end of the speedo hose hooked to. A pitot, or to the lower unit on th engine? If the speedo is driven off the engine lower unit, it could have debris in the pickup hole-a common problem that will affect how the speedo reads.

 

[cdnfthree2]

Re: Speedometer failing-Stuck at 20

Lower unit, I believe i t's clear but it was a little dark so I'll check again.

 

[Silvertip]

Re: Speedometer failing-Stuck at 20

If the speedo reads at speeds above 20 MPH, the pitot is not plugged and the tube is not kinked or damaged. If the speedo was permanently stuck at 20 MPH, then pressure in the tube might not be released which would indiate a plugged pitot or pinched tube but that does not appear to be the case. Pull the tube off the back of the speedo. If the needle doesn't drop to zero, you have something to add to your trash bin. Most speedos are sealed and you will wreck it getting it appart. Speedos are about $35 at most any store that sells boating supplies.