# Dixson wireless tachometer



## Mike C. (Jan 28, 2016)

Hi Guys,
I was wondering if anyone here has any experience with these small engine tachs?They are also sold under many other names such as Oregon.My father has one that is well over twenty years old and I dragged it out yesterday to check the maximum RPMs on the old Ariens ST824 and Allis Snow-Pro II,both with Tecumseh hm80 engines.

I've always felt that both of these motors were a tad gutless and the tach revealed that both engines were not reaching anywhere near their spec of 3600 rpms.Both were only hitting about 2800-2900 RPMs.

However,when I started turning the screws to bring up the speed,I didn't dare go beyond 3300 as the engines seemed to be really screaming.

I am now wondering just how accurate these tachs really are.The factory spec states an accuracy of +/- 2%,which would be an error of +/- 72 RPMs at 3600.

Considering the vintage of this device,I'm wondering how much aging of the electronic components is affecting its calibration.My other hobby is electronics and I am well aware how accuracy of test equipment degrades
with age and storage conditions.I would love to know how these tachs are calibrated at the factory but can't find that information.

I left the governors set to 3300 RPMs on both machines and tried them in about 4-6 inches of very wet snow.The increase in performance was surprising to say the least-throwing distance was greatly improved.

Does anyone know of something I could check this tack against to get an idea if it's even remotely within spec?I know,another tach would be ideal,but I don't have one.

Cheers,M.C.


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## snowworks (Dec 16, 2015)

How does it pick up a signal?? Hold it close to the plug wire?? I have an inductive lead to hook up to the plug wire and then a switch to set the number of times it fires per revolution. The Tecumseh should be 1:1 I have never used your style.


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## Mike C. (Jan 28, 2016)

Hi snowworks',

This tach uses a small,coil-spring antenna that's mounted on the top back of the unit.It rotates on a screw so you can fold it out of the way when in storage.You hold the antenna near the sparkplug and turn it on.It has a low rpm range that goes up to 5000 or so for 4-strokes and a high range for 2-stroke engines.It's for single cylinder engines only.

They're ridiculously expensive now ($100 plus),but I believe my father gave around $40 for his.Considering you can buy a digital one for less than $20,I'll bet they don't sell a lot of these now-but who knows?


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## classiccat (Mar 1, 2014)

A Sirometer is a nice thing to have in your toolbox (_you can probably find it much cheaper on fleabay_). The work on the principle of resonance & the vibrations of your engine; wherever you get the widest swing of the wire is the RPM you're running.

Most of my OPE has a Hardline tach installed semi-permanently...which is the kind where you wrap a wire around the plug wire.


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## UNDERTAKER (Dec 30, 2013)

What about this 1.:tongue4::tongue4:


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## Town (Jan 31, 2015)

POWERSHIFT93 said:


> What about this 1.:tongue4::tongue4:http://www.amazon.com/CyberTech-Dig..._UL160_SR160,160_&refRID=0H6EGP0GND8QAYGFVYFC


I have one of those. It is easy to use and works well. The reflective strips stay on the PTO and on the impeller even after some usage. So you can confirm engine rpm against impeller rpm for a rough confirmation against manufacturer specs.


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## skutflut (Oct 16, 2015)

Mike C. said:


> However,when I started turning the screws to bring up the speed,I didn't dare go beyond 3300 as the engines seemed to be really screaming.
> 
> I am now wondering just how accurate these tachs really are.The factory spec states an accuracy of +/- 2%,which would be an error of +/- 72 RPMs at 3600.
> 
> ...


One way might be to find another machine that is running correctly, and try your tach on that one to see what reading you get. If the known good machine has a throttle, you can get readings at a few different spots, and make note of your tach readings so you can figure the error. I just wonder how much spark voltage affects the accuracy, and what voltage older machines generate, vs newer machines.


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## RedOctobyr (Mar 2, 2014)

Verifying this tach, without another one available, is probably tricky. Using another engine will still raise the question of whether *that* engine is turning at the proper speed. 

If you have access to a generator, that should be 3600 RPM, in order to give the proper 60Hz output. Further, if you also have a Kill-A-Watt, that can actually measure and display the frequency of the output. With a generator and K-a-W together, you'd effectively have a tachometer for the generator. 

Apart from that, buying a $10 inductive tachometer from eBay might be the easiest solution. Plus you'd have a tach that you could leave attached to the machine, if you chose. And which doesn't require any permanent wiring for installation, you just wrap the tach's wire around the spark plug wire. 

There was a thread recently discussing options for tachometers/hour meters.


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## snowworks (Dec 16, 2015)

I see there is a few other choices out there.. Mine is a Fox Valley. needle swing and a few ranges for the RPM you are measuring. With a switch for the number of pulses per RPM. Inductive pick up on the plug wire. 9V battery powered. Has been working good for many years.


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## UNDERTAKER (Dec 30, 2013)

POWERSHIFT93 said:


> What about this 1.:tongue4::tongue4:http://www.amazon.com/CyberTech-Dig..._UL160_SR160,160_&refRID=0H6EGP0GND8QAYGFVYFC


What is the difference between these 2.


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## Grunt (Nov 11, 2013)

POWERSHIFT93 said:


> What is the difference between these 2.


 $27.99
-$16.99
------------
$11.00

Otherwise, they appear to have the same operating ranges. :icon_whistling:


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## UNDERTAKER (Dec 30, 2013)

Grunt said:


> $27.99
> -$16.99
> ------------
> $11.00
> ...


Welllllllllllllll that much I already knew. BROTHER GRUNT.:tongue4::tongue4:


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## Town (Jan 31, 2015)

The more expensive one uses 3 AA batteries and in the product description the distance to target range is given as up to 6 ft.

The cheaper one uses a 9 volt and the target range is 2 to 20 inches.

Mine is like the cheaper one (9 volt battery), but the target range is listed as up to 10 inches for the red LED target light (to know you are seeing the reflective tape) and 20 inches for the laser measuring light. The red light range exceeds 10 inches because the device is held on the safe side of the spinning 12" auger and shows up on the back of the impeller, so that must be 20 inches or so. The red LED light targeting feature makes the cheaper one more desirable to me.


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## Mr Fixit (Nov 19, 2013)

A common electric motors turn usually at 1725 RPM. A table saw motor will turn 3450. You can check your common mechanical or laser Tach.s using them motors. Then verify your spark wire tach.s from this first tach.'s reading. You can't find a more accurate subject to test.


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## Mike C. (Jan 28, 2016)

RedOctobyr said:


> ........
> 
> If you have access to a generator, that should be 3600 RPM, in order to give the proper 60Hz output. Further, if you also have a Kill-A-Watt, that can actually measure and display the frequency of the output. With a generator and K-a-W together, you'd effectively have a tachometer for the generator..........
> 
> ...


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## JLawrence08648 (Jan 15, 2017)

classiccat said:


> A Sirometer is a nice thing to have in your toolbox (_you can probably find it much cheaper on fleabay_). The work on the principle of resonance & the vibrations of your engine; wherever you get the widest swing of the wire is the RPM you're running.
> 
> Most of my OPE has a Hardline tach installed semi-permanently...which is the kind where you wrap a wire around the plug wire.


How do you like your Sirometer aka Briggs Vibrameter? Is it accurate?


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## classiccat (Mar 1, 2014)

JLawrence08648 said:


> How do you like your Sirometer aka Briggs Vibrameter? Is it accurate?


I like it so much, i don't know where it is at the moment (_probably in my shed_) :grin: 

They're nice to have in a pinch and fairly accurate with a little practice.

The downside is that you need to have 2 hands on it; keep it against the engine & turn the dial with the other.

Plus, when you've wrenched on enough engines, you ear knows when it's overrevving or lugging.

Inductive tac that can be fastened giving you both hands to work the machine (or carb, governor spring tension, etc.) while monitoring RPMs.


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## gibbs296 (Jun 22, 2014)

IPhone app. Might try it...https://itunes.apple.com/us/app/engine-rpm/id340401811?mt=8


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## nastorino (Jan 28, 2016)

gibbs296 said:


> IPhone app. Might try it...https://itunes.apple.com/us/app/engine-rpm/id340401811?mt=8


Does that really work? Did you verify against one of the tachs that was listed above?


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