Speedometer doesn't work?

A

Arkboater

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Joined
May 24, 2007
RO Number
26432
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I have a '89 Cheetah ski boat and the only instrument that doesn't work is the speedometer. It has the little plastic finger that goes into the water on the bottom of the transom. I have no idea how these work so any advice or recommendations for things to check would help! Thanks all! I love this site! It's been a big help!!!

Jared
 
Mine stops working about 3 months after it gets fixed. Those speedos are POC in my opinion. Get yourself a handheld GPS to track your speed accurately. Worth the money......
 
Thanks flutter!!!!! I have a GPS I bough in November and I haven't even thought of that! Thanks!!
 
Have a great summer!
PrettyLady.gif
 
I will start using my GPS, BUT, is there anything pretty simple/easy that I might want to check on the speedo though?? I would like to get it fixed even though I have a back up idea now, thanks to flutter.

Jared
 
look for a clogged tube. even a spider web will do it.
 
The plastic finger is called the pitot tube. They are one of the least accurate means of measuring speed of a boat but it's still interesting to see a speedometer needle move, and sometimes they can be surprisingly somewhat accurate. Try clearing the pickup hole in the pitot with thin string trimmer mono or soft wire. At speed , water forced into the pitot compresses the air in the tube and moves the bourdon mechanics in the gauge. You might try blowing hard into the pitot end of the hose to see if the gauge needle will move at all or is frozen in place. If air travels freely , the tube or gauge is leaking. Make sure the plastic hose that goes from the pitot to the back of the speedometer is tightly fastened at the ends & in really good shape it's whole length. When the hose develops a leak it will spray water all over the area & that is often all over the wiring at the back of the dash. Especially bad if salt water & usually unnoticed until expensive damage has been done.The paddle wheel types are safer and generally a lot more accurate if maintained but they require their own gauge & 12V. Airmar also makes a no-moving parts ultra-sonic thru-hull speed sensor as well. The latter 2 types of speed gauges usually have the added benefits of trip log and often seatemp readout.

Keep in mind speed gauges display STW (speed thru the water) whereas GPS offers SOG (speed over ground,... or towards a waypoint), 2 different concepts with different results if the water is moving or wind is influencing the boat.
 
There is a small hole at the end of the pitot tube that faces forward. This can easily get clogged with junk in the water. Just take a paper clip, bend the end of it out straight, and clean out the hole. Unless there is some other problem going on this will usually do the trick.
 
Just remove the speedo and use the extra hole as a drink holder! Damned boats NEVER have enough drink holders! ;)
 
haha Mike! My boat actually has 6 holders and is only rated to carry 5 people! ;)
 
That is so that one of your passengers can be a two drinker!

No matter how many RPM the tach is reading, I'm only going 10MPH according to my speedo. I even go 10MPH in the slip until I shut down the ignition!!!
 
"No matter how many RPM the tach is reading, I'm only going 10MPH according to my speedo. I even go 10MPH in the slip until I shut down the ignition!!!"

Maybe you should have a conversation with "Bob" He"s figured out how to make his boat go as fast as he wants it to with his Speedometer.
He"s also got a GPS but I guess his Speedo is more accurate.
 
Another quick question...I pulled the tube off the pitot and blew into it to see if the speedo needle moves... It moves but just barely bounces. (at least that is what my wife said when I asked her to watch it) anyway, how much should it moved when I blow into the tube? (If you can't tell, I am a first time boat owner and am learning as I go along. haha ;)
 
If I blow air through my pitot tube, I can get the boat to go like 100mph!
 
Yeah, I figured that wasn't right. I knew I was blowing kind of hard into it and I figured water could force as much air as I was blowing into it. Guess it’s the gauge, the tube or something else. Oh well, guess I'll just stick with the GPS. It felt like I was blowing into a straw that you were holding at the other end. The air didn't move freely. I checked the tube from the gauge down the side of the boat and I couldn't find and kinks or anything. Guess I will have to look from where the tube goes into the back of the boat to the side of the boat. Should you be able to blow through it pretty easy, or should it feel like you are blowing into a straw that has one end held like I mentioned above? Thanks again ya'll!
 
ark, I'm afraid our silliness is getting confusing for you. Any references to flutterby and/or blouderback should not be taken seriously. Maybe we should butt out so you can get the information you need without any confusion. Sorry about that!
 
Well, like I said...I am a first time boat owner and I don't know hardly anything about boats so I would pretty much fall for anything at this point. BUT, I am learning slowly. Ok, back to the speedo question...any answer to my last question? Thanks.
 
Oops, sorry.
But truely, I used a can of compressed air that you use for cleaning computer equipment, and I was able to get the speedo to register like 60mph for a few seconds. Yes, it should fee like you're blowing into a straw that has the end capped, 'cause in fact, that's what the speedo's pitot tube is.
 
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