Engine Trouble Running great until...

[gary55]

OK, so i have spent maybe 12 hours in the past two days ripping her apart... losing my mind... i took off the head gasket, cleaned it up real nice and re-installed it... same with the carb and the exhaust.... so i can confirm i have absolutely no leaks... (no oil leaking anywhere). i took off the magneto and gave it a little buff with some sandpaper to give it a decent connection, i also checked for spark on the plug (while not looking powerful at all, it does appear to be firing) i took out the plug and ran it for idk like ten minutes with my drill turning the crankshaft (or whatever its called) to ensure it wasnt flooded, replaced the plug and still ive got nothing... cleaned the air filter... nothing.... i noticed that the spark plug appears to be a little short, and is not sparking like it did when i first replaced it a few days ago... still sparking but not as strong... considering replacing CDI and magneto assembly... also considering buying a whole new motor and using this one for parts...
Please advise

replace the CDI. You have already checked everything. The one thing that you can't check is a CDI that is intermittently operating. I have seen this on more than one occasion. I have seen them work well for a short time then go bad, then after setting for a while work well again briefly, then work poorly with no power. These CDI's will show little to no spark with a 8 heat range plug, some with a 6, but still not enough to run properly, and more with a 4. Still they are defective and will fail completely. I think this is the best possibility to explain your symptoms.

 

[Mr. Beaver]

replace the CDI. You have already checked everything. The one thing that you can't check is a CDI that is intermittently operating. I have seen this on more than one occasion. I have seen them work well for a short time then go bad, then after setting for a while work well again briefly, then work poorly with no power. These CDI's will show little to no spark with a 8 heat range plug, some with a 6, but still not enough to run properly, and more with a 4. Still they are defective and will fail completely. I think this is the best possibility to explain your symptoms.

i owe you a great many thanks, as well as many thanks to those who helped me previously, i have done two complete tear downs of the engine, finding only minor issues (buildup ect.) i purchased a new cdi and magneto and after installation she is running like the wind. Further note it has been rain today and is expected to rain again tommorow... any suggestions on how to protect my new electronics from being ruined by the rain? i noticed that the cdi does not appear to be water proof in the least, and electrical tape will only do me so good

thanks again

 

[CrazyDan]

Fill the edges of your magneto cover with silicon caulking and the same for the cdi, cover it everywhere it might leak.

 

[gary55]

i owe you a great many thanks, as well as many thanks to those who helped me previously, i have done two complete tear downs of the engine, finding only minor issues (buildup ect.) i purchased a new cdi and magneto and after installation she is running like the wind. Further note it has been rain today and is expected to rain again tommorow... any suggestions on how to protect my new electronics from being ruined by the rain? i noticed that the cdi does not appear to be water proof in the least, and electrical tape will only do me so good

thanks again

Glad to hear your on the road again. Like Dan said silicone caulking or gasket seal around the gasket and where the wires go into the mag. housing and CDI will help a great deal.