ATC 200 running weird, Help.

[toyota200x]

The neighbor has a 1982 atc 200 and he has never cleaned the air filter. So tonight I went over and took it apart. I washed the filer with the hose, dried the filter, and then oiled it. When we started it after this it was making this muffled chugging noise from the exhast. It seems to do it the most as middle throttle. What could this be. I adjusting the air screw but it didn't do much more than make it rev a little more while iddleing. Thank you

[PowerTrike]

The carb might just need a good cleaning. I'd say give that a shot.

[J.D.]

I'm with PowerTrike. Other things you can check are:

Spark plug. I've seen them with a bridge of carbon across the gap and they will run, but run like crap.

Take off the air filter. Even though it's been cleaned it could still be nasty and giving restriction.

Check the exhaust/muffler for restrictions.

Check and make sure the main jet is screwed in good. I just recently found out about this on my brother's Honda 200 dirtbike. It would start up fine, but as soon as you gave it gas, it would spit and sputter and not rev. His main jet was loose, screwed it in and had no more problems.

Good luck.

[TrikeKid]

id use more than just the hose to clean the filter as well. i'd check the plug if its a quiet pop it might be too rich.

[toyota200x]

Yeah it probably does need a good cleaning but it didn't do this before I cleaned and oiled the filter. This kid thinks that cleaning the air filter was bad for it and messed it up. Where is the main jet in the carb? I don't have much experiance with carbs. Thank you

[toyota200x]

I took the plug out and looked at it and it was black. I cleaned it off with a wire brush and put it back in. It still did it but he said it wasn't as bad. Does it make sense that it wouldn't do it in the winter?