Pressure Washer Tip pressures

[KE4AVB]

Anyone got anything on what I should be the line pressure be with various tips? Finally got myself a couple test gauges and just wondering. The currrent pump that I working on bypasses at 4200 psi with the trigger released and with the wide angle Yelow tip drops to around 800 psi.

Kinda someone already this info but I can develop my own chart.

Edit: Had customer to come in and test as I felt the operating pressure too low and uses this Cat everyday. He agreed that the pressure was still too low so new is on the way when he decides as want to if he had spare to get up while awaiting parts.

[KE4AVB]

Found part of the problem customer using a #4.5 tip when he should be using a #4 so that is going to lower line pressure somewhat but still thinking it be a lot closer to the 4000 psi. I either got a check not closing right or the packing is shot again. I should have just did a full rebuild instead of just fixing the obvious bad o-ring

Still learning these pump though getting better at as time goes by...First time I tried a short cut instead of a full rebuild. Cat parts are not cheap.

[Luffydog]

Looking at pressure washers yesterday. Have u seen the new sthil pressure washers they have out now. All of them had Kohler engines on them. Heard they was the only ones that would do the specs that sthil wanted. The colors anyways. That what I was told. Look to be a good looking washers.

[KE4AVB]

Hope I can get this tablet to work..

Are they horizonal or verticle units? Next time I'm at JD I'll see if they have any I can look at.

[KE4AVB]

How in the world anyone get things done with a tablet, may just be me just being used to a regular keyboard. I thought I was never get things right. Finally just went to my regular system for the rest of posts this round.

[Luffydog]

I was looking at the ones that was vertical but they said they had commercial ones that was bigger so guessing they might be horizontal. Got to talking to the salesman and isn't even finish looking at them he kinda talked me right out the door

[KE4AVB]

Yelp salesmen tends to do that. Don't have that with my JD dealer mostly they know that I am after parts most times.

Of the pumps I service the horizontals are usually rebuilt and verticals being just replaced as rebuild cost on a vertical is as much as a better new pump.

The 6DX I am working has one valve cap that for some reason got stuck at .020 above seating fully. I going be removing all the seals and plastics I can so I can take a torch to it to see if I loosen the cap. I know I am going to melt that one valve assembly. I done rounded off the cap with my Air Cat trying to remove it. I had hand install the cap down to o-ring and seems that the Red Loctite has seized the cap. I had no problem with the other five which I used the same loctite on. Once I get it off I will find out what is the culprit. It not the valve not being seated as I would not been to nearly fully seat the cap by hand. I figured I would run in this sooner or later. I have rebuilt enough these pumps that I need to start stocking the packing and valve kits; it just that a big ticket stock item for me that only gets used a couple times a year.

The customer did bring in another 6DX that I can rebuild the pump head so I going do a little experiment Monday to see if the packing is my problem or if it is the valve cap not seating the valve fully against it o-ring by installing the packing units into the other pump head.

The second pump was stored in 5 gallon bucket that leaked. The pump was submerged in water long enough rust had built up on it but all clean off when pressure washed it and bearing were tight so the pump actually still turns though by hand. Just got to change out the unloader as it has a different style on the pump head and there is Zero clearance on the current setup and it would not fit as it will need even more room.

Its nice to be able to do a divide and conquer tests on an unit for a change of pace. Most times I just go with my best judgement call on these. This one has throw me a curve ball with that cap seizing.

[KE4AVB]

Well after I changed the bad bypass valve the change over gave another 400 psi (Now 1200 psi) so it definitely the valve that I couldn't get cap fully down giving part of problem. Also found some bad packing too. So it will be a full rebuild of the second pump head.
Ordering two packing kit this time around along with a couple check valve kits. Ouch in one way but will save me time next rebuild.

On a side note about the new Loctite. Sunday I tried some of the blue and it was setting before I even got the air line fitting tighten up so the red probably did the same thing on me. A big change from my last bottle of Loctite.

[lee]

I just rebuilt an AR RKA4G40 4000 psi 4 gpm pump. It would only put out about 2000 psi on the gauge with the correct #4 tip. The valve caps came right off using my impact wrench. I checked the valves by using my little hand brake bleeder vacuum pump tool. It has a cup looking fitting that you can set the valve in and pull a vacuum on it. You can pull a vacuum on a good valve and it will leak down very slowly. A bad leaky valve won't even hold any vacuum. I put one of the old high pressure seals up on a plunger and it would slide back and forth pretty easy. A new seal is super tight. My low pressure problem was due to worn out high pressure seals. The valves were good as was expected as the pressure was low and steady not pulsating (which would indicate a leaky valve). Put it all back together and fired it up. Set the unloader to 4000 psi operating pressure and when you let go the trigger it will jump to 4500 psi. I didn't use any locktite on the valve caps, just torqued them to 40 ft lbs. I'm thinking your problem is the high pressure seals as well.

[KE4AVB]

The loctite was used per Cat service manual instructions. It just that something is awry in that one area and cause the cap to lock in place. I have rebuilt several Cat 6DX40, AR, and General pumps without problem. It just was that I tried taking a short on this one and it has bit me in the tail; should had went the full rebuild route. Oh well live and learn.

The main reason for asking about tip line pressures is that I just starting using an inline test gauge this year to make sure the pressures are right instead of going by feel. This is something new to me as I don't know what to expect reading wise. Of course you got to start somewhere. At least it will make diagnostics much easier from now on.

I already gather something from your reply Lee and that is what I thought I should be expecting, pressures to close to pump rate pressure. With the Cat being only 1200 in use and 4200 in bypass I do have a packing problem as I suspected. At least the ceramic pistons are okay.