How To Hook Up A Tach To 026

[West Texas]

How Do You Hook Up A Tach To an 026

I've always tuned my saws by ear; like the wav file on Madsen's site says. But today a friend gave me a small electronic tach; and, quite frankly, I don't know how to hook it up to the 026. I presumed around a plug wire and to ground; but, thought I'd get smart and ask first.

 

[West Texas]

The tack is a Kohler Engine "Tiny Tach" and the only way I've been able to get a reading from it, is to put the pickup wire on the plug wire. But the readings don't make a lot of sense, as it shows 2300 at idle and only 5500 at full throttle with bar and chain on it. I thought the 2300 might be valid until I read the full throttle reading; and, it would have to be a lot higher than 5500. So maybe its for the Kohler low rpm generators???? I'll go to the local auto parts shop tomorrow and see if I can get a regular auto tach??

 

[Lobo]

Some older model tach's did not go extremely high and if I remember well there were some also with dual scales, a high and low, perhaps you are on the lower scale. I have one which reads to 20 or 30 thousands rpm's and you do not need to hook up the wire just place it an inch or so away or near the plug if you prefer.

You can download installation instructions on Tiny-Tach's site for some models

http://www.tinytach.com/tinytach/installation_gas.html

 

[kevlar]

the stihl tach i use at work is wireless i hang onto the bar and hold the tach in my thumb and fore finger just above the saw and voila. instant reading

 

[West Texas]

According to the Tiny Tach web site the max rpm of this tax is # RPM to 9,990. I need to get one like the Stihl tach, wireless and with a higher rpm threshold. Thanks for all your input guys.

 

[Diesel JD]

Kohler is probably for a 4-stroke anyway....is it not? The kind of RPMs we see on saws are just not duplicated in even other 2-cycle applications like outboards and what have you. It probably maxes out around 5500 that's prob. why it is reading there...I don't know what the pros use for this...even in racing type cars the engines will only see 9K RPM!

 

[Lakeside53]

I use Stihls Tach EDT-5 and another brand I('ve can't remeber) that cost me $99. Both wireless.

Both figure out if you're a 4 stroke or 2 stroke, and can be made to read correctly for 2 sparks per 4 cycle or 1 (yes, many small engines spark on the exhaust cycle as well as the compression cycle - like Yamaha and Vanguard etc)

 

[bugfart]

If the unit is for 4cycle double the reading?
Of course thats a mean idle at that point...

 

[timberwolf]

If its a 4 cycle unit would you not half the reading, The tach counts the number of sparks then converts to RPM.

2 stroke 1 spark=1 rev
4 stroke 1 spark=2 revs

so a 4 stroke tach doubles the number of sparks per min to get the rpm. if a 4 stroke tach is used on a two stroke it would count each spark as 2 rpm, hence giving a false doubled reading.

I like the stihl tach, I tried others that clip on to the sparkplug wire and work optically, neither worked as well as the pricy stihl tach.

 

[bugfart]

Thanks.

 

[cbfarmall]

4 stroke 1 spark=2 revs

Not necessarily. Lots of 4-stroke engines spark every revolution. Typically, the firing is done off the flywheel: once at TDC and then 360 degrees later at the end of the exhaust stroke. When small engines still had points how would it fire other than every revolution? Of course, if the engine picks up spark off the cam, then you have a different situation.

Chris B.

 

[timberwolf]

True, some of the tachs have a switch 2/4 stroke, So you would have to know how the spark was initiated or at least recognize that the rpm reading was double what it should be.

34,000 on my 260 no, dont think so, flick the switch, 17,000 oh yeh, get it in the wood quick.