Mantis-20 tiller

mony0_8

Full Member
Joined
Dec 6, 2010
Messages
54
Points
8
My mantis isn't firing, does anyone know what the ohms should be for the cdi and coil?
 

grcauto

wrench
Joined
May 29, 2014
Messages
1,474
Points
48
It's a mag isn't it? Just replace it.
 

billr

wrench
Staff member
Joined
Mar 12, 2007
Messages
7,971
Points
63
I find very little info for a "Mantis 20"; and am surprised it would have CDI. What makes you think it is CDI? Maybe post pix of the engine/ignition components. Does this coil have two windings (primary and secondary), or is there only one high-voltage winding?
 

mony0_8

Full Member
Joined
Dec 6, 2010
Messages
54
Points
8
It's one of the first models, magneto and coil separate. Was running fine and quit. Not firing and hard to find parts.
 

mony0_8

Full Member
Joined
Dec 6, 2010
Messages
54
Points
8
Have resistance but not sure if its correct.
 

Attachments

  • 0527231957[1].jpg
    0527231957[1].jpg
    2.4 MB · Views: 5

grcauto

wrench
Joined
May 29, 2014
Messages
1,474
Points
48
Resistance checks on coils is only valid if the test fails. That means only no resistance or open is valid.
 

billr

wrench
Staff member
Joined
Mar 12, 2007
Messages
7,971
Points
63
Secondary maybe 10K ohms, or more. The primary will only be an ohm or two, too low to measure accurately with a common multimeter.

Does this have breaker-points; have you chased that black to find out what it connects to in the crankcase? Where is the flywheel/magnet in that picture?

To me, "CDI" means "Capacitor Discharge Ignition", much more complicated than what appears in the picture, and much more expensive than justified for a small engine like this. Again, why do you think it is CDI???
 

mony0_8

Full Member
Joined
Dec 6, 2010
Messages
54
Points
8
Haven't pulled the flywheel but can see part of the magneto under it. I've been building 2-stroke 66/80cc bike engines for a few years and they have the CDI is why I thought it was one also.
 

mony0_8

Full Member
Joined
Dec 6, 2010
Messages
54
Points
8
It is a CDI. 4.9k at coil and .64k at magneto.
 

Attachments

  • 0528230811_HDR[1].jpg
    0528230811_HDR[1].jpg
    2 MB · Views: 6
  • 0528231125[1].jpg
    0528231125[1].jpg
    2.2 MB · Views: 5
Last edited:

billr

wrench
Staff member
Joined
Mar 12, 2007
Messages
7,971
Points
63
Well, I read-up enough on Kioritz/Echo/Yamabiko engines to believe that is CDI, not Kettering. I better leave you be. I have no clue what all the bits and pieces of that system are, much less what typical coil resistance would be.
 

grcauto

wrench
Joined
May 29, 2014
Messages
1,474
Points
48
Weak spark or none? If the magnet is strong just throw a coil on it.
 
Top