I have a 6 hp MTD mower and the only way to start it is, take spark out, then squirt a little carb cleaner in the hole, replace plug, then it starts right up. The primer in the front does not seem to be working. It is not hooked up to the carb, looks like it just blows air into it. Any help?

 

There is a gasket between the air cleaner box and the carb body. This gasket seals the primer circuit and it will not prime if this gasket is bad. Also, if the gasket around the bowl rim is bad or missing, it will not prime. The primer pressurizes the bowl with a small amount of air and forces a small amount of fuel into the carb throat.

 

I have noticed that these cleaner bases are prone to warpage. We have had good luck in proper primer operation in these cases of using two cleaner gaskets instead of the usual one.