Hi Gadge, Would be a good idea to move these post away under another title so as to keep your original topic clear. My belief is that the problem I am having has nothing to do with the amount of vacuum, it is the piston coming up on compression that is closing the valve too early, but why is it only on this configuration with the motor turning a belt. The weight of the blade carrier should compensate for this but it doesn't and why do I not get any of this sort of problem with the F/C ones. It is doing my head Another thought I have had is trying one of the F/C decomp type that can be opened up and fitting a stronger spring This is maybe another idea https://www.ebay.com.au/itm/2pcs-De...XP-350-STIHL-029-066-MS260/323779330084?
