Service. Pump sounds ‘crunchy’

[Truckcab79]

Got a couple of jobs booked shortly wher I’ll need my pressure washer. It’s a Jetmac 7hp Loncin 15LPM unit

It’s been laid up all winter. Filled with oil. All
Linkages oiled etc.

Started up to warm the oils for an oil change started fine. Had already back-flushed the pump as last time it was laid up it didn’t want to self-prime.

All fine (ish) but low on power. Press the trigger and I’m getting pressure but nothing like I should. when I release the trigger the pump gives a little ‘crunch’. I’m going to change the oil anyway. Didn’t want it to run for too long like that. Any suggestion as to what I should do. Loathe to run it too long in the hope that there’s some seal in there that’s dried out but will sort itself, in case I do some damage to it.

Engine also isn’t revving up when I press the trigger but otherwise all seems fine.

 

[Truckcab79]

All oils changed. Pump, gearbox and engine. No sign of metallic particles anywhere though I didn’t run it for long.

 

[Truckcab79]

Started up again. Seemed to run fine at first. Good pressure. Then same thing started again. Noticed that new gearbox oil was milky which would suggests it’s mixing with water but having drained a little off I can’t work out whether it’s water or just loads of tiny bubbles. Have left a sample to settle.

Any ideas?

 

[Truckcab79]

Gearbox oil used was EP90 for info.

 

[Truckcab79]

So……Reasonably sure the seal has gone between water pump and gearbox. Anyone direct me to what I might need and how to replace unless you can think of another reason?

Pics of pump and box below.

 

[Truckcab79]

Also not sure why this would cause the lack of pressure intermittently? Surely it would run normally until I knackered the gearbox by running it with thinned oil? What am I missing?

 

[THL4KEL]

Give Terry at Jetmac a call. Is it still under warranty, if not he will probably be able to tell you exactly whats up with it.

 

[Truckcab79]

Give Terry at Jetmac a call. Is it still under warranty, if not he will probably be able to tell you exactly whats up with it.

I’ll message him but to be honest he wasn’t very helpful when I had a minor issue with it previously and it was about a month out of warranty. It’s only done 20 hours.

 

[THL4KEL]

You're better off getting 20l litre container of 4/1 (water/anti freeze) and running it through machine when you close down for winter months. Protects the seals..

 

[Truckcab79]

You're better off getting 20l litre container of 4/1 (water/anti freeze) and running it through machine when you close down for winter months. Protects the seals..

Cheers. Any idea what seals I need to replace?

 

[Deleted member 7446]

I'd say possibly trapped water / moisture over winter and it's cracked the internals

When you stored it over winter did you keep the ball valve open along with the high pressure output. If not any residual water will freeze within an air tight confined space

The best thing to do is to strip it down and identify the point of failure

We are unable to diagnose something we can't physically see unfortunately

 

[THL4KEL]

Ideally it's good to use someone local that knows pressure washers inside out and let them have a look at it. They will more than likely carry the part needed and get you back up and running fast.

I have bought equipment off all the big companies that everyone on here goes on about and there is not one who I would say gives good after sales care...

 

[Truckcab79]

I'd say possibly trapped water / moisture over winter and it's cracked the internals

When you stored it over winter did you keep the ball valve open along with the high pressure output. If not any residual water will freeze within an air tight confined space

The best thing to do is to strip it down and identify the point of failure

We are unable to diagnose something we can't physically see unfortunately

Cheers.

I’ve had the pump and gearbox split. Looks brand new. Hadn’t appreciated how little is actually in the gearbox. Makes me think I’m wrong about that being an issue though the oil still went milky / bubbly of course. Zero signs of wear. Can’t honestly say I can see any water ingress either and having had it apart can’t see that the water would get to that part of the box anyway. Just oil and tiny bubbles in there. I’ve just put it all back together and am going to run it again. After that I suppose strip down pump?

I take it unloader valve wouldn’t have any bearing on this issue?

I’ve contacted Jetmac but no reply as yet.

Not convinced whether I’m right about oil migrating into pump either.

 

[Truckcab79]

Could be a load of red herrings for which I apologise. Ran it again and all fine. However after about ten minutes the crunch when I release the trigger was back. Finally located it and it’s the unloader valve. When I release trigger it moves downward and with quite a bang / crunch. Could be just sticky after winter I suppose but I’ll guess I better learn how they work and take it apart. Pressure however remained fine so it works, but I’d rather sort it.

Any pointers?

 

[Truckcab79]

And oil (from same container as last lot), no longer foaming.

 

[THL4KEL]

Might off been a seat valve jammed through not being used.

 

[Deleted member 7446]

Could be a load of red herrings for which I apologise. Ran it again and all fine. However after about ten minutes the crunch when I release the trigger was back. Finally located it and it’s the unloader valve. When I release trigger it moves downward and with quite a bang / crunch. Could be just sticky after winter I suppose but I’ll guess I better learn how they work and take it apart. Pressure however remained fine so it works, but I’d rather sort it.

Any pointers?

Having bubbles in oil can be a multitude of issues
Overfilled oil can cause cavitation due to the lack of space and it's aerated by a crank or gears
Also moisture ingress or lubricant contamination

The crunch could be needle bearings failing worn component parts

 

[Truckcab79]

Might off been a seat valve jammed through not being used.

On the unloader?

 

[Truckcab79]

Having bubbles in oil can be a multitude of issues
Overfilled oil can cause cavitation due to the lack of space and it's aerated by a crank or gears
Also moisture ingress or lubricant contamination

The crunch could be needle bearings failing worn component parts

The crunch turns out to be more of a bang and is the unloader popping downward when I release the trigger. Not sure why as I don’t yet know how they work to be honest.

 

[Deleted member 7446]

The crunch turns out to be more of a bang and is the unloader popping downward when I release the trigger. Not sure why as I don’t yet know how they work to be honest.

 

[THL4KEL]

On the unloader?

No on the pump head. There are six brass bolts that when removed the seat valves can be found. They can get jammed after not being used for a long period of time or when the pump is brand new. You can get them working again by running a hose pipe through where the machine draws water. They have probably freed themselves up while you have been trying to get it going. There was a good video on You Tube by Q Washers of how to test them but I can't find it...