can anyone help me figure out why my yamaha wolverene 350 is blowing black smoke. It idles great but when I throtle it up, it runs rough and blowes black smoke. I cleaned the carb. changed the air filter.

 

Is your exhaust tip have an oily coating on it? it could be shooting oil because mine has done that before.

 

not yet. but I'm sure it will if I can't fix it. what was the problem with yours.

 

I needed to jet it

 

what do you mean " you needed to "jet" it"

 

The jets in the carb are not correct

 

Thanks for answering. do you think this would cause fuel to spit back into the air box. Thats what mine is doing. It seems like its getting more gas than it can burn. I've adjusted the slide piston and it helped some. could my timing be off.

 

I had a similar problem. If you have an aftermarket air filter your jetting may be different. Try a smaller jet. Running too rich (more gas then needed for the amount of air) will cause you to burn more gas and therefore black smoke. Other than that make sure your intake is clean as well as your airfilter.

 

if you have a diaphram type carb you could have a hole in the diaphram so you are getting gas but your slide is not lifting and it is flooding your motor I have seen this when people put large K&N filters and take the lid off of the air box without putting in a lighter slide spring it won't have enough vaceum to lift the slide.
Remember Black smoke equals to much gas and white smoke equals burning oil.
Hope this helps you out.

 

take it to the dealer and have the carb adjusted. that is the most simple solution.