Honda tiller FG1100K1AT with GX25 engine. 4 cycle miniature tiller on the line of a mantis tiller, a very good machine! The problem is that oil comes out of breather tube into carburetor intake while engine is running. It saturates the breather element and drips out the bottom onto the tiller shroud.
After taking the valve cover off and finding it with a lot of oil in it, I cleaned it out to determine the flow of the oil and why it puts a couple drops out the breather tube every minute.
It appears that oil is pumped up to the valves and enters a plastic distributor of some sort found in the valve cover. The distributor has 5 exit holes that I found; one on each end out of the distributor and three hard plastic tubes incorporated into the distributor with exit holes. One pointing toward the engine and the other two pointing the opposite direction. It appears that the sealed chamber this distributor sits in fills with oil for lubrication of the valves and then returns the oil to the engine through a square shaped hole near the top of the chamber. The problem I see is that the breather hole is lower than the return port to the engine body.
There is a maze the oil must travel through and a metal filter that can pass oil into or out of the chamber on the path to reach the breather port leading to the carburetor. It seems that with the return port higher than the breather port, the oil finds it's way out of the breather exit hole into the carburetor.
This must be confusing to some one not familiar with this engine, and I must certainly be missing something, but could some one please explain how this is to work and why I am getting so much oil into the carburetor via the breather?
The engine starts well and seems to run OK, but with only holding about 2 1/2 oz of oil, it won't take long to remove this small amount of oil through the breather hole! Resulting, of course, with a constant need to check and fill the oil and the tiller getting coated with oil and dirt grime because of this.
The oil is checked on a dipstick after the engine has been rotated 90 degrees from it's normal working stance to it's storage stance (sort of on it's face). Too much oil will just run out the filler hole when sitting this way. not allowing it to be over filled.
Could it be that blow by pressure is forcing the oil out of the engine due to wear? this unit hasn't been used very much.
Any help would certainly be very much appreciated.
Rex
