motor missing and backfiring

[bigdtbone]

briggs motor18.5 hp OHV . It cranks and runs but governer is hunting runs a bit rough .Backfiring thru carb once every 10 sec. or so. When you engage the blade it taks off but still hear some backfiring and slightly rough run. I cleaned the carb . no change. What do I do next ? model 31p707-0124-e1

 

[pugaltitude]

Simple things 1st.

Clean fuel?
Tank and lines clean?
New spark plug?
Also do you have excess oil in air filter housing?

 

[bigdtbone]

I drained fuel and refilled with new. new spark plug. no oil in filter . I could see a little trash in tank . this is a 2 year old mower. it dose have a fuel filter . thank you for your help .:smile:

 

[Mikel1]

Is it still under warranty?
Backfiring thru carb sounds like a valve issue.

 

[bigdtbone]

No warranty .Just looking for some ideas what to try next ?

 

[Mikel1]

Have you checked the flywheel key?