was running fine for 2 months thatn started puttering

[Dustyn B]

so I got the 80 cc as a gift. Much needed I put an hour a day on it at least. until today it started puttering while at a light. than on my way home it died on me while running. I checked the spark plug and I'm still getting spark. been using the same mix of gas for the last 4 tanks. I checked the walls and made everything tight again. now, can someone tell me what is wrong with this!!!!

 

[bluegoatwoods]

Hmmm........I guess you'd better have a look at the carburetor and make sure that fuel is getting to that point.

If that doesn't pan out then I'd look at spark again. I've heard that a bad plug can show spark when it's lying against the head but not actually spark when it's in the head, under compression.

The stock magneto, CDI, spark plug plus wire and boot are not really very high quality and one or the other might be getting weak. And they're cheap to replace, at least. So is the carburetor.

 

[KenM]

Yes, I agree with Mr. Bluegoatwood. Check the carb. Replace the spark plug . I have gone through two already , in only two hundred miles.
And I had a lawnmower spark plug show spark when you check it but not work under load in the engine. Hope this helps you. Ken. Keep looking up!

 

[crassius]

check that motor mounts are tight too

 

[Purple Haze]

If the mag coil got wet, it's probably toast. Remove the cover and if it's wet, replace the mag coil and use RTV around the hole where the wires come through the case. If dry, probably a sticky carb float or needle. Clean thoroughly and check float level: 21mm or eyeball holding upside down you should just see the edge of jet above float. Hopes this gets you going.

 

[Dustyn B]

yea I'm getting told by a few people even, outside the website that it might be the fuel, hence the carb. ok I'm checking it out right now. thanks for all the feed back.
if a sticky float is a real thing than it sure makes sense. how would I get to the mag coil? I disconnected the kill switch from the cdi.

 

[Dustyn B]

the carb had gas in it. the float wasn't dry, spark plug would be the next thing right? and bluegoatwoods, what do you mean by boot?

 

[mikedabomb]

The "boot" is the thing that clips on top of the spark plug and it is connected to a fat wire coming from the CDI box.

I would like to know more info...did it chug/sputter to death or did it make a low moan/whiney noise, without any clear "chugs"?

How long did it act like this before it died?

I'd spray some mixed gas unto the air intake for the carb, and if it starts, it's not able to get any fuel through the jet(s) or there is a vacuum leak which would suck more air instead of fuel from the carb.

By checking the cylinder walls, you at least rule out engine failure.

It might be the gasket for the case leaking? I think this would be pretty unlikely though. Hardest to replace too, so check this last over what everyone above is suggesting.

 

[Dustyn B]

It sputtered till it died. I haven't been able to start it again yet. when I drop the clutch its extremely easy to pedal, easy enough to do circles in the garage. I'm thinking now something is wrong with the piston, I had this same problem with the 175 Yamaha me and my father built. Piston problem causing no pressure.I still have to replace the spark plug, it happened for 2 days, 1 while on my lunch break and on my way home, 2nd day it just got me to work, had to pedal back home. just have to wait till payday to buy ay parts than put them on 1 at a time too figure out what it actually was I guess. Isn't here any reason I would lose compression?

 

[crassius]

could be head gasket went bad