I have a Genie Z-45/25 manlift. The primary boom function works ok extending to lift boom but doesn't want to retract to lower boom. It seems to malfunction worse as the hydraulic system heats up. all other functions seem to work although some functions take more time to react at times. the primary boom circuit seems to work when system is cold and as it warms up it takes longer and longer for the cylinder to retract until I get to a point where the cyl won't retract at all. If I let it cool off I can grt thr boom down. It reacts the same whether using the basket controls or the ground controls. Terry Z
I think your talking about the straight boom with the two cylinders side by side and not the z boom and it sounds like the holding valves in the bottem of cylinders aren't releasing because of adjustment but you need to pull the cylinders first and check the piston packing Ive seen it be worn or blown just enough that the boom will lift but bypasses to much to open the check valves on boom down just like your describing
When it starts messing up, how does it work using auxiliary power?
Thanks for your response. My machine is a Z lift. I adjusted the set screw on the lockout cartridge and got it it to move down; however it still takes a lot longer for initial movement than the cylinders on the secondary boom. I am going to order a new lockout valve. Thanks again. Terry
the primary boom has 1 cylinder and holding valve and the 2ndary boom has 2 cylinders and 2 holding valves the primary does have a short cylinder back next to the pivot thats a master cylinder for the basket leveling cylinder. you can go on genie web site for parts and service info. we just had to go thru a lot of cylinder and valve and electrical work for a customer on one just like yours that had been setting for 5 years and they wanted to get it back going for training operators.