Speedo inop on starcraft

[bobb729]

Hi folks I own a 2006 starcraft futura and the speedo tach does not measure boats speed. I checked the hose in back of the speedo to the engine and blew air thru it and no clogs. While replacing the impellor did not see any problems with pick up. Any way I can check the speedo itself?

 

[Texasmark]

Re: Speedo inop on starcraft

I don't remember the air pressure, whether at 100# or something like 40. If I knew the #/sq in of water pressure at say 30 mph and the square inches inside the meter chamber then a swag might be closer.

I think what I did was to stick the air chuck on the rear of the speedo and just bump it (quick shoot of air) looking for the needle to deflect. Figured I could get on and back off before it hurt anything and as I recall it worked ok.

If the meter is made out of zinc, I have found the inside corroded sometimes and if the corrosion is bad enough could stop it from working. Another test of the meter is to disconnect the water line while running and see if water is coming out of the hose at the rear of the meter. If so, sounds like a meter problem, if not, pickup or distribution problem.

HTH,
Mark

 

[metriccrescentwrench]

Re: Speedo inop on starcraft

First off, understand that a boat speedometer is just a pressure gauge (sort of). The relationship between speed and pitot pressure isn't linear, which is why many boat speedos have a non-linear scale. In any case you should be able to apply air pressure to the speedo and get an accurate reading. With 5 psi you should see around 18 mph, 10 psi should show about 26 mph, and 15 psi should show about 32 mph. Be careful not to overpressure the speedometer, that could cause damage.

 

[bobb729]

Re: Speedo inop on starcraft

ok i will make sure to watch the pressure i am using

 

[Don S]

Re: Speedo inop on starcraft

Is this an IO or an OB. If IO, what drive?