2003 Nissan 9.9 HP 4-Stroke missing at higher RPM's

[mills]

Picked up a Nissan 9.9 HP 4-Stroke. Carb is absolutely clean, new spark plugs. Took the carb apart and made sure all the small orifices are clean. Starts right up on first or second pull. Idles great. BUT misses badly at higher RPM. Changed out the coil with another one. Same issue. Pulled the flywheel to be sure all is well. Plugs look black and sooty after running at higher RPM's. CDI unit???

 

[pvanv]

What is the actual model? When was the carb actually properly cleaned?

 

[mills]

What is the actual model? When was the carb actually properly cleaned?

Sorry but no model sticker. It is a long shaft tiller manual start. I took apart the carb 2 days ago to be sure it was clean.

 

[mills]

Sorry but no model sticker. It is a long shaft tiller manual start. I took apart the carb 2 days ago to be sure it was clean.

 

[pvanv]

Probably a 9.9B or B2. Looking in the carb does not clean the passages.

 

[mills]

Probably a 9.9B or B2. Looking in the carb does not clean the passages.

I took the carb completely apart including both jets. put small wires thru all orifices and soaked it in carb cleaner.

 

[pvanv]

Sounds too rich. What main jet is installed?

 

[mills]

Sounds too rich. What main jet is installed?

Paul,
You are right on! Sorry about the delayed response but we were gone for 2 weeks. I had 2 carbs for this motor. They had different size main and secondary jets. I installed the jets with the smaller size and it now runs GREAT. THANKS for your help.