I'm servicing the above lift- unit has a strange symptom- hydrauics work good until you turn the engine off. Once restarted, hydraulics take about 1 minute to come back to life. If you leave the forks up when you shut down the engine, lowering the forks will immediately bring the hydraulics to life. Once working, the hydraulics are strong with no aeration of the oil in the tank. Any input would be appreciated
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L1ft- thanks for the suggestion but the hyd. system still doesn't work for the first minute or so with the tank lid removed. It's strange that when they do come to life, they're as strong as ever. Pump doesn't seem weak & the pressure control valve doesn't seem stuck- the oil cdoesn't get frothy with air- any more ideas?
Thanks L1ft- I'll check that out when I get back. Never had a vent get clogged before- you learn something new everyday!
Check that the hydraulic tank vent is not clogged.
You might just leave the tank filler cap off and try it that way for a test.
My idea is based on the fact that if the tank vent is clogged and slow to allow air entry to make up for displaced oil, a partial vacuum or negative pressure might develop in the tank and cause the pump to "lose its prime" when the engine is not running.
And if you stop the engine with mast raised, lowering the mast would flood the tank..............and with a clogged vent.......the effect of the flooding return oil would be to "supercharge" the pump suction circuit resulting in instantaneous priming of the pump.
It bears checking out the vent system of the hydraulic tank.
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