Old JS150 issue

[ciaron]

Hi new to this forum hope someone out there can help. I bought an old JS150 working very well up until of late. I have notice a hesitant engagement for a second, then it works away. Last few days a slight lost of power not too frequent. This evening working for an hour with revs up after N hour or so it is losing power when needed such as going up a slight embankment or pulling loose stones to one side. There is a squeal from the fan belt. Rams are warm? I also
have a different movement in tracks when engaged pulling more on one side than the other?

any suggestions?

ciaron

[Stock]

So is it losing engine revs or hydraulic power............................................. .

[v8druid]

fan belt is either a real weird one or a red herring

LS fault on the VDP dragging the engine down

[ciaron]

So is it losing engine revs or hydraulic power............................................. .

Hydraulic power. Had someone look at today he got me to pull all in to see if power would stop. It didn’t, he wanted reeves on so I did and it didn’t lose power. He suggested that because there was black smoke (not much) coming from the exhaust that it was the power and needed a refit £4500!,,,,

how else can can I find out if the pump needs replacing?

[v8druid]

Hydraulic power. Had someone look at today he got me to pull all in to see if power would stop. It didn’t, he wanted reeves on so I did and it didn’t lose power. He suggested that because there was black smoke (not much) coming from the exhaust that it was the power and needed a refit £4500!,,,,

how else can can I find out if the pump needs replacing?

can't see as there's much wrong with the pump if it'll black smoke load the motor

[Muz]

might be some sort of unloader valve on the pump stuck on. These are used to make the swash plate go to zero at engine start up but sometimes they get stuck and cause all sorts of weird problems, engine labouring at odd times for example

[v8druid]

might be some sort of unloader valve on the pump stuck on. These are used to make the swash plate go to zero at engine start up but sometimes they get stuck and cause all sorts of weird problems, engine labouring at odd times for example

aye that sounds reasonable Muz ... the delta pressure unloader ... delta pressure is the low level/background circuit that provides initial pressure to make everything work ... IIRC usually around 30-50 bar