misfire on jw16

P

popsmazz1

Petty Officer 1st Class
Joined
Oct 13, 2006
Messages
276
I replaced the coils and plug wires, the problem is it runs fine except at low idle then it starts missing. I cleaned and gapped the points and checked the resistance, zero ohms when closed. tried new plugs, it will run ok for maybe 30 seconds at idle and misfire again. when it starts this it sounds like it"s running on 1 cyl. until the throttle is past start then the other cyl. kicks in. what now? it will run fine at half throttle and faster.
 
P

popsmazz1

Petty Officer 1st Class
Joined
Oct 13, 2006
Messages
276
Re: misfire on jw16

at this point I"m not sure of anything, but sounds like one cyl. cutting out.
 
lindy46

lindy46

Captain
Joined
Nov 27, 2008
Messages
3,886
Re: misfire on jw16

I assume you cleaned and set the points while you were under the flywheel? Points must be squeaky clean to operate properly. What about the carb? Have you cleaned/rebuilt it?
 
P

popsmazz1

Petty Officer 1st Class
Joined
Oct 13, 2006
Messages
276
Re: misfire on jw16

yes I did all that, lower cyl. misfires, put my spark tester on it running, has strong spark all the time, put a new j6c in it only misses a little, put in a rj12c and runs perfect will idle down never misses not even once. What the hell? thats not even the right plug, is an rj12c a hotter plug?
 
P

popsmazz1

Petty Officer 1st Class
Joined
Oct 13, 2006
Messages
276
Re: misfire on jw16

I am wondering if running that rj12c is going to hurt anything.
 
nwcove

nwcove

Admiral
Joined
May 16, 2011
Messages
6,293
Re: misfire on jw16

jmo, but stay with j6c or j4c. look elsewhere for the problem or you may melt a piston.
 
lindy46

lindy46

Captain
Joined
Nov 27, 2008
Messages
3,886
Re: misfire on jw16

If spark is strong, I'd look back to the fuel system. When you rebuilt the carb, did you remove the welch plug on top of the carb and clean the holes underneath? That is the idle circuit, and if not completely clean, can cause the problem you describe.
 
P

popsmazz1

Petty Officer 1st Class
Joined
Oct 13, 2006
Messages
276
Re: misfire on jw16

turns out it was a bad condenser, showed good spark, but my friendly repair shop guy said to replace the condenser, he was right.
 
You must log in or register to reply here.
Top