Decompression valve

[cascade]

My Sthil MS310 has become very hard to crank. I don't know if it has a decompression valve, but if it does it's defective.
what Sthil saw are equipped with decompression valves?

 

[Bob Hedgecutter]

If it was easier to start beforehand and this hard to start condition is just being noticed- it might be time for a carb clean and kit.
Excess fuel might be entering the system and causing a hydrolock like condition where too much fuel is present in a liquid form and liquid does not compress like gas.
They (the 310) do not have a decompression button- Stihl usually reserve those for the pro grade models, however saws like the 023/230 025/250 and the larger than 310 390 got them, so that does not always ring true.

 

[cascade]

Great reply. Exactly what I needed to know.