ShadetreeRet That's what I thought until I lost the cam on an 18 hp briggs. Decompression release was on the intake, yes intake. My 13 hp honda the decompression release in on the exhaust.
My 5 hp was blowing gas out the carb at least 8 inches, yet no back firing even though the engine was running extremely rich. That means the intake had to be closed when engine was firing on the power stroke while the intake was open during the compression stroke causing blow back through the carb. Sounds to me like there is decompression happening on the intake valve. I'll do some research on the engine. George