I have a friend who put a k&n air filter on a stock nikki carb. The stock nikki carb is non adjustable. if the k&n gives more air flow wont this make his engine run lean? theres no way he can make this work with out making the motor run hotter than fourty hells is it? btw its a 16hp lt bt.

These motors are not that sensitive. Use the K&N and drive it like you stole it.

Install an exhaust gas temperature guage a couple inches from the exhaust port in one of the exaust pipes and run it with the stock air filter and then with the K&N and I bet there will be a minimal difference as the original briggs carb runs a little rich in the first place. I'm 99% positive you should be just fine by running that free'er flowing K&N. Technically the motor should run a bit more crisp with the enhanced air supply. If interested, read about EGT guages on the internet and you will see they are your one of the most righteous peices of carb and timing tuning tools available. I have used them to fine tune a couple airboat carbs and distributor settings (timing) and they are a no brainer once you learn to interpret them. As long as your EGTs on the briggs stay at 1400 and below you should be just fine. Safe EGTs are a bit lower for air cooled engines as you need a little extra unburnt fuel in the combustion chambers to keep them cool enough to prevent the pistons from melting and the valve stems from warping. Hope this helps.