Mark42, or anyone with a 5-35mph speedo

[55Crestliner]

I've used the search function, lots of discussion about Pitot speedos, but there doesn't seem to be too many numbers being talked about.<br /><br />I have a brand new Vector speedometer, 5-35. It doesn't seem to want to show a reading until almost 15 mph, and it stops at 21 mph. <br /><br />I have checked using a GPS, the boat is going 25 while the gauge says 21. When I slow down, the gauge will show a reading of about 10, then drop to 0. When the gauge says 10, the GPS says I'm doing over 15 mph.<br /><br />The Pitot is not in line with any hull protrusions, is far enough from the prop, and was installed according to the height recommendations on the directions.<br /><br />Could the angle of my transom have something to do with this? What should the proper angle be?<br /><br />Boat is a 1950's Crestliner Commander.

 

[cuzner]

Re: Mark42, or anyone with a 5-35mph speedo

Pilot speedo's are not very reliable.I'm sure you already know they work from vacume.They are not very accurate, especialy at lower speeds.I only use mine to get general idea of how fast I'm going. You may want to check to make sure you don't have any kinks in the tube, other than that your better off reying on a gps for speed if you have one.<br /><br /> Jim

 

[sangerwaker]

Re: Mark42, or anyone with a 5-35mph speedo

True for most pitot speedometers, but the Airguide brand tournament type are very accurate, even at slow speeds. I've had them on 2 different boats and tested them against a GPS and they are very accurate. Tournament ski boats have been using them for decades.<br /><br />Thay look like this <br /><br />

<br /><br />Sorry, 55, I have no idea why your current speedo isn't working properly. Sounds like your set up is good if you followed the directions.

 

[snapperbait]

Re: Mark42, or anyone with a 5-35mph speedo

the Airguide brand tournament type are very accurate, even at slow speeds.

Airguides are the best, period.. Plus, they're adjustable..<br /><br />Crestliner, you're not the only one who's 5-35 vector don't read correct.. Saturday, mine read 32mph when the GPS read 22knots (25mph)..

Sumthin wrong there...

 

[Mark42]

Re: Mark42, or anyone with a 5-35mph speedo

55crestliner,<br /><br />Like you said, I have the 5-35 mph speedo (sportsman model). It should be the same mechanism as your Vector model, I believe. The guage has a very smooth sweep, seems to react quickly to changes in speed. This leads me to believe that you have an obstruction or kink in the vacuum line between the pilot tube to the guage. Check the routing of the tubing, and where it connects to the pilot tube. <br /><br />Are all 3 pieces new? (pilot tube, tubing, guage)<br /><br />This guage was designed to give accurate readings at lower speeds. That's why I bought it. But Teleflex does not define "accurate" with a spec. Regardless, it should move smoothly and not bounce or stick. <br /><br />I plan on using by BIL's gps this summer to verify it's accuracy. <br /><br />At any rate, check your setup. If you diconnect the hose from the guage, you should be able to blow through it easily. BTW, do not use compressed air to blow into the guage, it can be damaged. (take note that Teleflex lists the replacement pilot tube for "pressure driven guages", but I read elsewhere that the speedo runs off vacuum created at the pilot tube. I am confused.) <br /> <br />Snapperbait, 32 vs 25 is an idication that something is wrong. Has it always been that way?

 

[Mark42]

Re: Mark42, or anyone with a 5-35mph speedo

Update:<br /><br />This is a Cut&paste from Teleflex tech data. The bit about pressure calibration is interesting, as is the bit about "verdigris" that Snapperbait may take interest in.<br /><br />Mark. <br /><br />1. The pitot tube speedometer operates with changes in air pressure in the hose and speedometer. Water is pushed through the pitot into the hose compressing the air. This pressure increases as the boat speed increases, causing the gauge to read faster speeds. There must be air in the hose. When the boat is still and the hose is removed from the back of the speedometer no water should pour from the hose. If there<br />is, blow the water back towards the pitot until air bubbles exit the pitot. Reconnect the hose to the speedometer.<br /><br />2. Check the hose for kinks or sharp bends that may be cutting off air flow.<br /><br />3. If the speedometer is not working, check that the pitot has not kicked partially or all the way up.<br /><br />4. The pitot is weed resistant, however, debris can accumulate in its opening. Prolonged idleness in the<br />water may attract barnacles or algae. Be sure the pitot allows water to enter the hose.<br /><br />5. The speedometer has no adjustments. If the above checks don’t solve the problem, the speedometer<br />must be replaced.<br /><br />6. Sometimes when a speedometer sits in the environment for quite a while, as over the winter, the internal metal parts form a coating (verdigris). This may make it difficult for the speedometer to operate. However, it should recover with repeated use.<br /><br />7. If adjustable air pressure is available, standard calibration speedometers should react to the following pressures:<br />5 PSI = 20 MPH; 11 PSI = 30 MPH; 19 PSI = 40 MPH; and 30 PSI = 50 MPH.<br /><br />8. A standard speedometer using the Mercury/Mariner in the engine foot speed pickup will read approximately 10% faster than with a Teleflex pitot mounted to the transom. Speedometers with the suffix “M” after the Part Number are calibrated for use with in-foot pickups. To test as in (7) above:<br />5.6 PSI = 20 MPH; 12.6 PSI = 30 MPH; 22.4 PSI = 40 MPH; and 35 PSI = 50 MPH.<br /><br />9. If the hose wants to prematurely blow off the hose barb connection at higher speeds (to 80 MPH), clamp a plastic wire tie over the hose on the barb.<br /><br />10. The pitot should be mounted on the transom at least 6" from the tips of the propeller.<br /><br />11. When winterizing the boat, winterize the speedometer system also. Remove the hose from the<br />speedometer head. Blow air into the hose towards the pitot. Blow out any water that may be trapped in the hose. Leave the hose loose and the inside of the speedometer should dry out over the winter (if there is any moisture inside). Reconnect the hose before launching the boat (or the hose will pump water into the boat).<br /><br />Link to this doc: Teleflex Speedo Document

 

[55Crestliner]

Re: Mark42, or anyone with a 5-35mph speedo

Another update - I wrote a note to tech support yesterday, got a human written email within about 10 minutes - impressive.<br /><br />He said to take it back to the dealer I got it from and have them exchange it. Sounds good, but I also heard that from a chain auto parts store when I kept getting bad starters. <br /><br />I guess I'll try that, get an exchange. To answer the above question, yes, it's all new.<br />Mark42, is yours actually reading below 10?

 

[Mark42]

Re: Mark42, or anyone with a 5-35mph speedo

55Crestliner,<br /><br />Yes, it does register below 10. I noticed in the "no wake" zones and 5mph zones that it would register just off the 5, then when I slow the needle drops and hits the pin. I guess I was doing over 5mph! <br /><br />When the guage is reading 30 mph, there is 11 psi in the tubing. I would think that the water would have to travel far up the tubing in order to compress the air enough to build 11 psi. This makes me realize that their winterizing suggestions should be followed. And it can't hurt to blow the line clear a few times a season just to keep working at top effeciency!<br /><br />

 

[Mark42]

Re: Mark42, or anyone with a 5-35mph speedo

Crestliner,<br /><br />How did things turn out? Did you get to try the new speedo?

 

[saxis]

Re: Mark42, or anyone with a 5-35mph speedo

Sorry for butting in....<br /><br />Mark42, where did you get the guages for your boat? I was thinking of doing something similar on my red/white Fleetform, and the white guages you have look great!

 

[Mark42]

Re: Mark42, or anyone with a 5-35mph speedo

Hi Saxis,<br /><br />They are the Sportsman series guages from Teleflex. Go to the Teleflex web site and download their catalog with all the guages. They have some nice designes. Most suppliers carry them. Should be able to find them here on iBoats. <br /><br />Mark.

 

[Realgun]

Re: Mark42, or anyone with a 5-35mph speedo

Faria has some nice ones too I should be installing them soon. I needa new pitot and pickup too. Man that holes is getting real expensive.

 

[55Crestliner]

Re: Mark42, or anyone with a 5-35mph speedo

Originally posted by Mark42:<br /> Crestliner,<br /><br />How did things turn out? Did you get to try the new speedo?

Glad you reminded me, I still have not taken it back for another one - need to.

 

[55Crestliner]

Re: Mark42, or anyone with a 5-35mph speedo

OK, got the new speedo, tried it out yesterday. It's actually quite accurate, according to GPS. At slow speeds, (it will register down to 6mph), it's dead on. When the boat is going 22.5 on gps, it said 21mph. Good enough for me, I mostly wanted to see change, and know if I was speeding in no wake zones.<br /><br />There's one thing that's interesting though, if not irritating, and that's it seems to stick. If I give the speedo a little flick, it will change to the current speed. It might say 15 mph, but if you slow down, it might drop to say, 10mph. Give it a flick, and it will drop to say, 7mph or whatever. It's not a big deal, but it's something to keep in mind. It also needs a flick when accelerating sometimes too.<br /><br />Makes me wonder, maybe the other one wasn't bad?<br />Anyway, I'm happy with it now, it does what I want. The Tiny Tach tells me much more of course, but it's not easy to glance at, whereas the speedo is.<br /><br />Thanks for all the replies.

 

[Richard Petersen]

Re: Mark42, or anyone with a 5-35mph speedo

I have never found the spedo useful. Tach, yes. No wake, posted areas, to variable on a weather basis. I do not boat in speed zones. They are sure tickets.

 

[Mark42]

Re: Mark42, or anyone with a 5-35mph speedo

55Crestliner,<br /><br />Did you blow your tube clear of any water before installing the new guage? I'm wondering if that has anything to do with it. Also, remember that the guage runs on pressure, so when you drop speed rapidly, the hose has to dump water through that tiny hole in the pilot tube. That could give the impression of the guage sticking. I think that if I slow quickly the needle does drop in two or three increments, but always is smooth on acceleration and small change in speed.<br /><br />I am thrilled to hear it reads close to GPS speed in the low 20's, because that is where I spend a lot of crusing time.<br /><br />Mark.

 

[55Crestliner]

Re: Mark42, or anyone with a 5-35mph speedo

I replaced the whole set, pitot, tubing and all - it was an easier return that way. I'll check out the "sticking" issue more next time, maybe that's all it is. Even if it is sticking, I'm still happy with it now.