Yamaha speedometer quit working

WRCuddy22

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Apr 9, 2004
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25
2000 200 Yamaha Saltwater with new gauges worked for a while and quit. Checked all fittings and blew low pressure air into the fittings from the motor back to the speedo and it worked. Got it all the way down to the fitting at the lower unit and from there down it is PLUGGED. Tried blowing air from top of lower unit down and nothing going. Dealer I bought the motor from said air usually does the trick. Any other remedies that would help. My service manual for the motor doesn't really give much of a breakdown. I may just add an external pitot tube like the old motor had. Seems to be a common problem with the built in tubes. I know a guy with 2004 Johnson 4 stroke with the same problem but the air trick worked for him.
 

Ray Neudecker

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May 25, 2004
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1,656
Re: Yamaha speedometer quit working

A small hand held drill with very small bits is about the only other option. All of these type pickups are notorious for clogging. Most of the bass fishermen here use GPS and have quit even trying to keep the pitot holes cleaned out.
 

huanca

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Nov 13, 2003
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Re: Yamaha speedometer quit working

I am not sure how yours is but mine (140 BET)unplugs near the lower unit. In fat, you have to unplug it to take the lower unit off. From there on you can use a wire hanger to clean the tube downwards. Good luck
 

WRCuddy22

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Re: Yamaha speedometer quit working

The connection by the lower unit is the one which I blew air down. I tried fishing a wire down it and ran into something solid. I didn't know if it was a plastic 90 degree fitting or an obstruction. How is the tubing connected to the exterior of the motor. I am guessing that the pickup is the small hole with the groove in front of it. I don't want to force anything too sharp in there so I don't punch a hole in the tubing.
 
D

DJ

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Re: Yamaha speedometer quit working

Pitot tube speedos are notorious for this kind of trouble. Plus, they are dreadfully inaccurate.
 

the machinist

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May 7, 2002
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Re: Yamaha speedometer quit working

My '92 150 was plugged so bad with salt crud when I bought it that I could not even find the pickup hole in the lower unit. When I had the lower unit off last fall replacing the water pump, I located the hole. It is about a 3/32" hole dead center in front & about 2" & above the gearbox's bullet nose.<br /><br />You will probably have to drill it out as, if I remember right it is a 90 degree inside corner drilled from the top & then from the front, meeting inside. I would not open it any more than it is already as the water pressure on it is equated to the speed. Drill it & then blow air thru the disconnected plastic tube.
 

swist

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Jul 1, 2004
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Re: Yamaha speedometer quit working

"I would not open it any more than it is already as the water pressure on it is equated to the speed."<br /><br />Correct me if I'm wrong as my experience is in air dynamics, but the size of a pitot opening shouldn't make any difference, as it is measuring pressure of the water, not volume, I know it's a little counter-intuitive, but making an opening bigger won't effect the pressure seen at any point. Analogy to electricity is if you increase the size of a wire carrying a current, the voltage (pressure) will not change, but the wire can carry more current (volume).<br /><br />Practically speaking though, if you enlarge the hole you probably make it even more susceptible to picking up crap....
 

WRCuddy22

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Apr 9, 2004
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Re: Yamaha speedometer quit working

Thanks for all the help. Machinist hit it right on the head. I wasn't sure where the pickup was, went out and looked and it was plugged solid. Took a small drill bit and twisted it in by hand till it cleared. Works great now. Thanks,<br /><br />John
 

jasell

Seaman
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May 30, 2004
Messages
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Re: Yamaha speedometer quit working

I got about the same problem. But i wonder how deep I should expect to drill measured from the front edge. I have not taken my lower unit of.<br />I also wonder if the hole is made right from the aluminium. I expecte that the owner before me put a stainless plugg into this hole.<br /><br />I got a Yamaha 90 from 2000.
 

rodbolt

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Sep 1, 2003
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Re: Yamaha speedometer quit working

hello<br /> the small tube is actually replacable. never seen it done nor had to do it but I saw the procedure. just use a small 1/8ths bit or so in your fingers and clear the small bits of wood and debris from it, when you clear it it will most likly dribble some nasty smelling water in your hand :) . no need to chuck up the drill. I personnaly use a small hand drill set for cleaning torch tips.
 

WRCuddy22

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Apr 9, 2004
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Re: Yamaha speedometer quit working

I wouldn't have known there was a hole even there. The mud dobbers must have found it and filled it. I tried blowing air into the tube from the top of the lower unit and no go. The area that was plugged was on the front of the engine and it was plugged about 3/8" thick. I just used a drill bit and worked it out by hand. Started real small and when it opened up I moved up to larger bit. The motor is buried in a snow bank right now so I can't give more details as far as location.<br /><br />Rodbolt, I finally got the news on the "new" 9.9 T9 hi thrust for 2005. They actually upped the displacement and now share the same block as the 15. This also increased the weight about 8#.I was leary about replacing my 9.9, which melted down last fall with 400 hours, with another 9.9, especially after reading the other thread. I'll be attending boat shows to decide what kicker I will add to my 22' Whaler. I kind of like the power tilt addition of the T8. Also checking the Honda Power Thrust 9.9, and I guess Merc got into the Hi thrust picture also. Has the Yamaha T8 hi thrust been a reliable motor?
 

rodbolt

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Sep 1, 2003
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Re: Yamaha speedometer quit working

so far it has<br /> we have a few sailboats with them and on cat that has a pair.<br /> all of them like the tilt function.
 

Triton II

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Nov 23, 2004
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Re: Yamaha speedometer quit working

jasell wrote<br />
I also wonder if the hole is made right from the aluminium. I expecte that the owner before me put a stainless plugg into this hole.
The speedo pitot in my FT60 lower leg just above the bullet is lined with a very thin wall stainless sleeve... so I expect all Yams with this feature are the same.
 

jasell

Seaman
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May 30, 2004
Messages
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Re: Yamaha speedometer quit working

OK, what will happen if I drill to deep?<br />-will I penetrate the gear house?<br />-How deep should I expect to drill?<br />-Are there any signs that can tell me that I'm about to go to far?<br />(my shop manual from CLYMER doesn't even mention the pitot tube.)
 

Ray Neudecker

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May 25, 2004
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Re: Yamaha speedometer quit working

If you try to use an electric powered drill, very likely to break it off before it goes far enough to matter. You are not going to drill through that stainless insert with a small bit thats hand powered. If you break the bit off, its over. The boat mounted pitot is a lot easier to service or replace.
 

rodbolt

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Sep 1, 2003
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Re: Yamaha speedometer quit working

no need to chuck it up. hold it in your fingers and twist it in.they clog with weeds and debris.
 

Triton II

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Re: Yamaha speedometer quit working

DJ says they're dreadfully inaccurate. I tested mine yesterday on very flat water at the bottom of the tide. Compared to the GPS the Yam digital reading from the pitot (which I cleaned thoroughly) was within a knot when running flat out both up and down river... so it's more accurate than either my motorcycle or my car. I was doing this to try out my new prop so I let everything settle down for a while (managed about five minutes at WOT 6000rpm and 30.7kts) without seeing another boat). Poor old FT60 took it in her stride and I was amazed how accurate the speedo was down to about 15kts. As lower speeds, it's a different story... the digital pitot measured speed varied by as much as 4 knots when the GPS read 10. So, sure, the Yam pitot system isn't too brilliant at slow speeds, however it's pretty good everywhere else... at least in my case.
 

swist

Senior Chief Petty Officer
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Jul 1, 2004
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Re: Yamaha speedometer quit working

. so it's more accurate than either my motorcycle or my car.
Law of averages. Mine is way off from my GPS (reads high). That is when it is working (not clogged).
 
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