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Pony motor only fires one at a time

ZGrant231

Well-Known Member
Joined
Sep 11, 2017
Messages
73
Location
Oregon
Working with a my D7 17A. I went to move it out of its cover this spring and had a hell of a time getting the pony going.
After swaping carbs, plugs, checking valves, points and compression I accidentally knocked a plug wire off and it started right up.
Now with both wires hooked up, all I get is an occasional pop or backfire. As soon as I lift a plug wire off the plug it will run like a champ on one cylinder, doesn't mater what plug wire is disconnected, but one will have to be removed inorder for the other to fire and run the pony on a single cylinder.
Re install the unhooked plug wire while it's running it runs horrible and eventually dies and will not restart.
I'm sure some one with more experience has some insight on this issue.
 

epirbalex

Senior Member
Joined
Aug 5, 2017
Messages
548
Location
Akitio
Occupation
peasant
Working with a my D7 17A. I went to move it out of its cover this spring and had a hell of a time getting the pony going.
After swaping carbs, plugs, checking valves, points and compression I accidentally knocked a plug wire off and it started right up.
Now with both wires hooked up, all I get is an occasional pop or backfire. As soon as I lift a plug wire off the plug it will run like a champ on one cylinder, doesn't mater what plug wire is disconnected, but one will have to be removed inorder for the other to fire and run the pony on a single cylinder.
Re install the unhooked plug wire while it's running it runs horrible and eventually dies and will not restart.
I'm sure some one with more experience has some insight on this issue.
could be a cracked magneto cap , a condenser or coil fail . I'd replace the condenser , you won't need a caterpillar one , just one you can fit
 

Joel59

Well-Known Member
Joined
Mar 11, 2013
Messages
153
Location
NY
Agreed. You've got a magneto issue. I'll bet the problem is in there.
 

LG 78

Well-Known Member
Joined
May 3, 2020
Messages
79
Location
King Country NZ
Try swapping the HT leads over on the plugs
If your getting backfires and wont start etc it may be possible that she is not timed properly
Is it a Bosch or a Wicco mag?
 

ZGrant231

Well-Known Member
Joined
Sep 11, 2017
Messages
73
Location
Oregon
I assumed it's a Wilco with the three screw cap. Unlike my other 4 screw bosh mags.
 

epirbalex

Senior Member
Joined
Aug 5, 2017
Messages
548
Location
Akitio
Occupation
peasant
Wico magneto should have 4 screws holding the cap on at least . Another issue is a leaking rotor , if you remove it , take off the brass spring clip and put some insulation tape around the shaft enough to hold the rotor firm and insulate it , works a treat on mine . If the mag is an impact mag the timing is either correct or 100% wrong . Large key way drive can only fit two ways . Should be X's on the mag and in the slot , it is easy to change as the leads just swap as there is no telling the leads are in the original place anyway .
 

ZGrant231

Well-Known Member
Joined
Sep 11, 2017
Messages
73
Location
Oregon
Couldn't sleep, thinking about it. Just got back in after midnight. Drove out and checked with a flash light. Wico 5M2850 #70391771 with 3 screw cap.
I ordered a Wico mag kit for the 5M2850 points, brush, cap, rotor, condenser,coil,coil bar, gasket....
 
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