My honda gx610 in leaking oil out of the exhaust, any suggestions to why it is?

i can help you what do you need to know

The return fuel line should connect to the gas tank.

Goto smallenginewarehouse.com there u will get your specs

most likely it could be the valve cover gaskets. is this a 4 cylinder or a 6 cylinder?

Grinding the valves will not affect the oil consumption or carbon build-up in the exhaust. Carbon can be from a rich mixture of fuel, but then the carbon will be a light powder that will rub off easily. If the carbon is hard and baked it will be a combination of fuel and oil, and the only ways you can get excessive oil int he exhaust is if the valve stem seals are leaking or if the rings are worn. Worn rings will make the machine smoke all the time but valve stem seals will make it smoke on first start-up of the day and also when you have rev-ed the machine and suddenly closed the throttle.

is this on the exhaust port or inlet port and which cylinder buddy

If it is carb version check if auto choke is getting power. If fuel injection replace temp sensor (common fault).

turn your car on, check for smoke coming from your exhaust pipe, it should be white, if so let me know