Have a Speedometer hose question

[CaptainMak]

Well, while doing routine maintenance to the bellows, etc with the bell housing off, I decided to check what was wrong with the speedometer as the needle doesn't move while I'm under way.

I tried blowing into the hose as hard as I could, but could only make it go up to about 20 MPH on the dial. Is this normal or should it read higher ? How would I know if there's anything blocking the passage ? How would one test the accuracy of a speedo gauge ?

Any input appreciated.

 

[airshot]

Re: Have a Speedometer hose question

If you could blow up to 20 mph then your good. They just work on pressure and it is a crap shoot as to there accuracy. I have had some in the past that were way off and some that were quite close. My current one is quite good after 10 mph when compared to my GPS but at lower speed they are way out. The pitot tube must be in the correct position for the speedo to work, they are easily bumped up and out of position by debris in the water. They are supposed to do that so they don't break off. Make sure your hose (tube) is solid, cracks can open up in hot conditions and cause them to not work.

Airshot

 

[achris]

Re: Have a Speedometer hose question

If you can blow to 20mph you have a great set of lungs!

If the speedo is not registering while under way, check for kinks in the hose, or debris in the pick-up. Are you using an external pick-up or the one in the drive? The only way to check the accuracy of the speedo is with another instrument, usually a GPS. If you have a smart-phone, download one of the free GPS apps and use that... Or if you have a chart-plotter on the boat, use that...

Chris......

 

[CaptainMak]

Re: Have a Speedometer hose question

Nevermind guys. Found info here: http://forums.iboats.com/boat-topic...ics/speedo-pitot-tube-replacement-626685.html POST #12. Just in case anyone else in the future needs the reference.

 

[CaptainMak]

Re: Have a Speedometer hose question

If you can blow to 20mph you have a great set of lungs!

If the speedo is not registering while under way, check for kinks in the hose, or debris in the pick-up. Are you using an external pick-up or the one in the drive? The only way to check the accuracy of the speedo is with another instrument, usually a GPS. If you have a smart-phone, download one of the free GPS apps and use that... Or if you have a chart-plotter on the boat, use that...

Chris......

Chris, my cheeks were about to explode plus my neighbors were probably thinking I was smoking crack or something blowing on that tube like that. :facepalm: I'm gonna crack the lower later on this week and check out the pitot tube in there. Maybe run something down it to clear debris. BTW, the one I have is the integral, built-in one. I have a GPS on the boat, but hate the idea of a dead gauge in the cluster.

 

[CaptainMak]

Re: Have a Speedometer hose question

If you could blow up to 20 mph then your good. They just work on pressure and it is a crap shoot as to there accuracy. I have had some in the past that were way off and some that were quite close. My current one is quite good after 10 mph when compared to my GPS but at lower speed they are way out. The pitot tube must be in the correct position for the speedo to work, they are easily bumped up and out of position by debris in the water. They are supposed to do that so they don't break off. Make sure your hose (tube) is solid, cracks can open up in hot conditions and cause them to not work.

Airshot

From what I understand, the pitot tube might be blocked inside the lower leg. How is the pitot tube bumped ? When the lower gets serviced ? Do I need to drop the bottom to re-set it ? thanks

 

[achris]

Re: Have a Speedometer hose question

From what I understand, the pitot tube might be blocked inside the lower leg. How is the pitot tube bumped ? When the lower gets serviced ? Do I need to drop the bottom to re-set it ? thanks

He's referring to the external pick-ups. They have a 'kick-up' feature to reduce the chance of them being broken off on impact (P.S. doesn't help, they break... :facepalm

Chris....

 

[CaptainMak]

Re: Have a Speedometer hose question

Just an update to close out the thread. It was sand/clay/wood mix that was stuck about 1.5 inches into the pickup tube. A small drill bit, some time and it all came out with some left over water. EZ fix.

 

[Flyboy42880]

Re: Have a Speedometer hose question

I had the same problem with mine. Easy fix! Amazed how fair I had to clean mine out. Definitely recommend doing it by hand as to not drill into the lower gears... Safety wire worked good to get the last bit out.