I recently purchased this machine that has been sitting a while. It starts right up and idles up and down fine and will run full throttle with no miss or sputtering. Whenever I try to track or lift boom it will bog engine down to the point of stalling engine if I don't let off. Once I let off it immediately runs to full throttle. No lights on instrument panel. I've put new fuel filters on it drained fuel tank and dropped the center piece out and washed tank. Alot of water and and sludge was in the bottom. I've also removed intake air filter tube going to turbo just to make sure it was getting plenty of air. Nothing made any difference it still acts exactly the same as it did when I picked it up. I still need to change hydraulic filters but I'm not convinced that's the issue because there is no pump whining or flow issue that I can tell . The engine does not smoke and sounds perfect at full throttle. It just bogs it down Whenever I use the hydraulics, I did notice however if I boom up and stick in at the same time it did not seem to pull the engine down as hard. It still did but not near as bad so that does have me wondering if its something with hydraulics. Did record the throttle cable linkage whenever i would use it to make sure it wasnt letting of the throttle under load and it doesnt. I also tied the full shut off selonoid in on position to make sure it wasnt causing any issues either still no difference. Where do I go from here? Is there something sticking in injection pump or maybe mechanical lift pump not building enough under load (alot of water in fuel whenever i picked it up)? Or bad boost leak? Or could the hydraulic filters be plugged enough that it restricts so much it pulls the engine down? Any help would be appreciated I'm going to get the rest of the filters changed just thought I'd see if anyone had some ideas in the meanwhile.