Chainsaw Repair

Husqvarna - Stihl - Poulan - Jonsered - Dolmar chainsaws and more => Stihl => Topic started by: flatsix on December 19, 2013, 12:43:25 pm

Title: Stihl 4-mix engines : how to set tachometer : 360° or 720° ??
Post by: flatsix on December 19, 2013, 12:43:25 pm
Hello,

Does anybody know how many Sparks/revolution of the crankshaft ?

Normally I think the 4-mix motors act like a 4-stroke, thus: 1 spark each 2 turns of the crankshaft = 720°

I bought a tachometer TT20 , and I wonder which setting to apply for reading correct rpm : is it 720 or 360??

Thanks,
Title: Re: Stihl 4-mix engines : how to set tachometer : 360° or 720° ??
Post by: Cut4fun on December 19, 2013, 01:57:37 pm
I steer clear of these. But willing to learn something new.  Searching for info.  I'm thinking like you 720

copy paste = The STIHL 4-MIX Motor runs in comparison to the common 4-stroke engine with the usual petrol-oil mix (1:50). The 2-stroke mix is distributed through a bypass channel to the enginer and thus ensures complete lubrication.

http://youtu.be/eWZfRdm9u9c
Title: Re: Stihl 4-mix engines : how to set tachometer : 360° or 720° ??
Post by: Cut4fun on December 19, 2013, 02:01:32 pm
Something in here on 4 mix  http://www.k2dt.com/library_files/2901.pdf
Title: Re: Stihl 4-mix engines : how to set tachometer : 360° or 720° ??
Post by: flatsix on December 19, 2013, 04:39:12 pm
In a week or so I will have my tachomter. It is adjustable for 720 - 360 - 180 - etc.

When it is there I will give it a test to see witch setting it must have - I think 720° (1 revolution each 2 turns)

When I know I will post the result.

Thanks anyway for your feedback  ;D
Title: Re: Stihl 4-mix engines : how to set tachometer : 360° or 720° ??
Post by: 660magnum on December 19, 2013, 04:54:12 pm
The four mix spark plug fires every time the piston passes TDC just like on a B&S
Title: Re: Stihl 4-mix engines : how to set tachometer : 360° or 720° ??
Post by: flatsix on December 19, 2013, 05:42:47 pm
What does that mean for the tachometer?  Should it be set at 360° or at 720° to read the right amount of rpm? ???
Title: Re: Stihl 4-mix engines : how to set tachometer : 360° or 720° ??
Post by: Eccentric on December 19, 2013, 05:48:41 pm
What does that mean for the tachometer?  Should it be set at 360° or at 720° to read the right amount of rpm? ???

Set it for 360°.
Title: Re: Stihl 4-mix engines : how to set tachometer : 360° or 720° ??
Post by: flatsix on December 19, 2013, 06:09:47 pm
O.K. I'll do that ! ;D