i have a 763 and ever since ive had it the lift arms are very slow. there is some hydraulic issue because if you bottom out another circuit at the same time as lifting it will operate normally. its mostly noticeable at idle or half throttle. if you run the machine at full throttle it "almost" works fine. its atleast useable the way it is and its just a yard machine so really havnt ever tried to fix it. it only affects the lift arms going up. arms down, tilt, and aux all work fine. it also drives fine. its more noticeable when its cold then hot but usually just run it full throttle. im thinking debris stuck somewhere in the valves? ive seen some people replacing pumps. could pump be weak and thats causing it? been running it this way for 10+ years..... https://youtube.com/shorts/W095GDj0s04?feature=share
Make the aux. hyd's. aren't engaged or partly engaged.
i would think ive already eliminated that as a possibility? engaging the aux actual makes the arms go faster.... and bottom out the bucket tilt also makes it go faster. what im thinking is the lift circuit is relieving at a lower pressure or the fluid is bypassing? im not the greatest with hydraulics.
something else i noticed this morning im not sure if its normal but if you bottom out another circuit (aux or tilt) while the arms are going down it stops them from going down. literally dead stop they will not go down while another circuit is deadheading.
Does the boom drift?
if you mean drift like bleed down? no not when running. when its off it will bleed down slightly like any machine does. not even that bad though ive seen much worse bleed down.