ive been struggling with a 84 200es. i pulled the top end off the engine replaced all the seals rings, reseated the valves. im getting great compressin and i set all the valves properly. the timing is set perfect. I get a great spark but when i put the plug into the engine nothing. it just won't spark when the plug is in im guessing. i poured gas directly into the cylinger and got nothing. is it a cdi problem a stater problem? any help ive never had this much trouble with one of these engines!!!!!!!!!!

 

Is it a brand new plug? If not, put one in.

 

yeah its a new plug. is there a way to check the cdi box to make sure its putting out a pulsating spark instead of a constant spark.

 

when you say you had great spark, how did you check it? was it out of the cylinder and grounded to the jug while cranking? if not, do it that way. also, if you would check the spark in a dark room/garage. then you'll be able to see if the coil wire is releasing energy prematurely through cracks. i've seen that before. but in situations like this, usually a new spark plug works as previously mentioned.

 

okay so today i replaced the plug, nothing changed when i check for spark i do put the plug against the cylinder, it has great spark. have't got a chance to check the plug in the dark yet, but by any chance does anyone have a manual they could email me at yz250jk@aol.com, that would be very helpful. and thank you all for the help so far.

 

Hi,
i work for Autolite spark plugs. You may have a weak coil. Typical if you have spark in open air and no spark under compression. Take an old plug, open the gap to .0100 (wide). Then check for spark. If it jumps that big of a gap, your issue is elsewhere