Question about petit-powered spedometers and water pressure gauges.

[12Footer]

The speedometer movent of these pressure-powered speedometers...Are they the same type of gauge as a water pressure gauge. I tore a junk one appart, and it looks just like a jacket pressure gauge inside.....Only much bigger.<br />Do these two gauges read water pressure in the same way? If so, I figure I can hook my useless speedo up to a water jacket fitting, and have a very nice,backlit,easy-to-read jacket pressure gauge.<br />What do ya think?

 

[evin300]

Re: Question about petit-powered spedometers and water pressure gauges.

I would Think that would work 12Footer. I would hook it up to a air compressor with a good gauge and see what 40psi looks like on the meter, mine runs around 5-10psi at lower speeds and 30+ at high speed.<br /><br />If I remember correctly it takes about 50psi to show 70mph on my speedometer, I wrote it down somewhere but cant find it, doesnt really matter. I would be nice if 20psi used up about half of the speedo. Good Luck, Good Idea!

 

[12Footer]

Re: Question about petit-powered spedometers and water pressure gauges.

In that case, Evin, I think it'll work My speedo only reads to 45MPH, so I'll check the pressure requirements, and have one massive water jacket pressure gauge.<br />Kewl!

 

[csmithrc]

Re: Question about petit-powered spedometers and water pressure gauges.

12Footer, if you check out Teleflexs website they have a chart showing what pressure matchs the mph.It is 5psi=20mph,11psi=30mph,19psi=40mph,and 30psi=50mph.It says that for Mercurys/Mariner w/foot pickup will read about 10% faster.I don't know if this applys to non teleflex speedometers.Hope this helps.

 

[12Footer]

Re: Question about petit-powered spedometers and water pressure gauges.

FOLLOW-UP; <br />I tried it out today in a test drum,mocked-up with some air fittings and such,just to see if it would read,and if so, if it would damage the movement. <br />No damage, but it read less than 10MPH on a 45MPH gauge. I just needed someting relative,so I'll try a 0-60PSI Water pressure gauge off of a well pump. LOL.<br />The things a guy will do to save 30buks,and a new hole in the helm

 

[letsbarbq]

Re: Question about petit-powered spedometers and water pressure gauges.

hello 12footer,<br /><br />i was thinking the same thing last night. did you happen to do it yet? I called the local shop for a water pressure gauge and they said that the kit cost about 50-70 bucks and that i should Tee it off to the main water line in the back of the block. <br /><br />i was asking him if it was ok to tee off to the pee hole where the water goes out. he said nope. not right.<br /><br />can you assist me with this?

 

[12Footer]

Re: Question about petit-powered spedometers and water pressure gauges.

LBBQ, I tried a 0-30 PSI air gauge,and it did not read. This is when I did some reading in the book about water pressure at the head of my engine being 5-8PSI normal.<br />I don't have a gauge that reads this low, but don't see why it wouldn't werk..I since got sidetracked on other "projects".<br />But the wrench is correct, it won't read doodly at the tell-tail,as there is zero back pressure at that point. You will find a threaded plug in the block close to the head,usually requires an allen wrench to remove it. This is where you would install the fitting for the gauge.<br />I also considered affixing a thermocouple out of an old oven on the block,and using an MVDC meter as a temp gauge,but didn't want to make an ugly mess on the side of an allready ugly engine <br />But it should werk in principle.

 

[Dhadley]

Re: Question about petit-powered spedometers and water pressure gauges.

As for OMC motors -- you "T" into the overbord indicator hose on a crossflow and into the incoming on a looper.<br /><br />I've thought about this before but never tried it. I guess if it didn't work maybe there really isnt 20 lbs (for instance) at the read point when the pump actually is putting out 20 lbs. More or less a calibraited or corrected read deal I guess.<br /><br />Interesting. Let us know how you make out.<br /><br />BTW -- 60 lb OMC water pressure gauges are really cheap at www.surplusunlimited.com but is the gauge only. You still need hose and a fitting or "T". The only downside of a 60 lb gauge on a crossflow is you will use less than 1/2 the dial.<br /><br />Let us know!

 

[letsbarbq]

Re: Question about petit-powered spedometers and water pressure gauges.

12footer, dhadley.<br /><br />i did it. for less than 25 dollars in parts, i did it. and it works like a charm.<br /><br />i unplugged the hose that the water pee from. i tee it off as close as i could to the engine block. i ran a hose from there to the gauge. started up. -- was worried for alittle because the water was weak...i gues it had to make its way to the gauge. then it worked. when i am on the water hose, the psi is weaker than when i am in the water. <br /><br />heres my psi range for a yamaha 150 1988.<br />idle-4psi @ 1000rpm<br />22 psi @ 5000 rpm. <br /><br />now i can monitor the water pressure and know when that water impeller needs changing.<br /><br />again here are the list of parts i got.<br />any used 30psi water pressure gauge and hose- $20<br />small hose clamp at autozone $2<br />small plastic tee at autozone $2<br /><br />tools needed- drill, door knob drill.<br />duration-1 hour.<br /><br />had to take apart some stuff and remove siding, gunwales. <br /><br />HELPFUL HINT !<br />since I already removed all the siding and gunwales in order to run the water hose from the outboard to the gauge. I ran a long string with it. This way, in the future when i want to install another gauge(water temp, etc.) I wouldnt have to remove all the stuff again. All I would have to do is tie it to the string and pull it through. Just make sure its long enough to pull back.<br /><br />just my @#$%@$% sunday. <br /><br />"Da Bears"