speeco replied again:
Aaron,
That sounds normal to me that it is bogging down in tougher pieces of wood. That is the pump shifting into the second stage. How large around are the pieces that are stalling the engine? Are you running the engine at full throttle?
Big difference between bogging down the engine and stalling it. Even with my 35 ton Speeco I manage to bog the engine from time to time, especially when pushing a four way head, but you never should end up actually stalling the engine. Here is how it works.
Chunk up a round, and engage the directional valve. Ram pushes forward on the first stage and engages the wood. As pressure increases, the pump drops into its second stage, somewhere around 500psi. Pressure increases, and of coarse load on the engine slows down RPM.
When it reaches 2800PSI and the round still hasnt split, the safety pressure relief valve in the directional valve releases, bleeding off any pressure beyond the set point of 2800 PSI. Generally its at this point you hear the tell tale squealing sound.The engine continues to bog because its still pushing up close to that 2800 PSI range, and will continue to do so until you release the directional valve handle. At no time should the engine actually stall.
If the engine is stalling, its either a problem in the pump not shifting down,or an obstruction on the outlet side of the pump up to the valve, the valve itself, or the relief valve not lifting soon enough. If its just bogging, any number of things like the governor on the engine not adjusted correctly or not working period, poor fuel, or any number of things including expecting more than what the machine can do.
If you know that the machine is not shifting down into the second stage, its a problem with the pump, because as I said before this is all done at the pump and has nothing to do with the valve, hoses, cylinder, operator, congress, Obama, or the chilli cheese fries you had for lunch.
No matter what the problem is, if you know its not shifting down, then take it back and bring the biggest, meanest, and ugliest girl you can find along with you to convince the store manager to give you a new one or your companion will drag him into a cattle water tank for an afternoon romp session complete with orange marmalade and cheez whiz.