Mini Digger unable to lift itself

[tonyirish79]

Hi all, first time poster here!

I was looking at a 3.5t mini digger today (1988 Yanmar YB351, about 5000hrs); all looks to be ok with it (tracking straight, track chains not worn, engine quick to start etc) except she was unable to lift herself fully using the dozer blade and boom together. It would lift one or other end of machine at a time but not both together, so looks like its only fit to lift 30-50% of weight of machine. I also lifted it up on each side using boom to inspect track sag; no problems here with lifting.

I also found the boom, dipper and bucket movements a little sluggish unless the engine was revved well over halfway (2450rpm max from engine plate), but maybe this is normal for this machine.

Could this be an indicator of weak or worn hydraulic pump? or engine? or both? The engine loads and black smoke comes from it if I press the breaker pipe pedal (blanked off).

I was under the impression that all mini diggers should be able to lift themselves fully & have been trying this test successfully on a couple of Kubotas.

Thanks for all help here guys. I would have bought her today but this threw me.

Anthony

[drew3650]

when was the filter last changed on the pump ?
think id try there first as not all folk think filters need changing,had it happen to me a couple of times with vehicles ive bought.
hope this helps

[garry]

what sort of mini digger is it

[essexpete]

what sort of mini digger is it

1988 Yanmar YB351, about 5000hrs