I just bought a Schwing P88, 2001 model with a Wisconsin motor.  Rough but Cheap.  Well i tried to use it on a on job for a test run.  It'll pump and it will build pressure (evident when it made the hose bounce when we started) BUT IT WOULD NOT PUMP AT A HIGH VOLUME. JUST a little more than a TRICKEL OUT OF THE HOSE.  I have about 4 years experinece with a Mayco in the past so I know what is should be doing. 

Im guessing that the springs are wore out but it confuses me because my macyo was a wore out and i know the springs were too and it always pumped adequate volume if it pumped at all.

ANY SUGGESTIONS WOULD BE GREATLY APPRECIATED

the roll pin on the rhs piston arm  might be broken, then it loses stroke and main spring tension

Just checked the roll pin. Its not borken.  And it actually looks like it has plenty of stroke.  But I know the return spring is wore out because the rocker arm was not riding the cam, when i pumped concrete.  It was bouncing up and down and slamming it.  Idk maybe the piston isnt drawing back and loading up because that spring isnt working.  I ordered a return spring last night from Schwing.  We shall see if that helps. 

Low volume with the cam follower arm not staying on the cam indicates cavitation. The comp side of your pump requires back pressure to work correctly, which you don't have because your not getting enough volume. Check the condition of the balls and seats. Make sure the seats aren't worn and the the balls are not full of water or slurry. If that's not it, it's probably the concrete.

Thanks for the ideas! 

The balls are worn but not cracked and dont have any holes and the seats are about the same.  Im sure it would'nt hurt to replace them too. 

THE CONCRETE MAY HAVE BEEN THE PROBLEM.  I asked for Pea gravel, which is usually small round sones (river gravel). But the concrete I got had aggregate that looked like someting between SB2 and chat.  But it was .5" minus.  May try chat mix next time.

One more question.

My prevoius experinece in pulling the seats has not been very good.  Is there an easy or correct way to get some leverage on them to get them out.

Bigger pry bar. If you're going to replace them - use a torch.

Basic mix proportions for ball valves;

594 lbs cement

70% sand

30% pea gravel

You reliaze the pump only pumps on the crank side right? The spring (comp) side just reduces surge. Even with no spring it would pump the same volume, just with more surge.

If   the  Tee manifold has a hole or leak the  pump will have a slower than average  output, but it would be intermittant, speeding /slowing back and forth.Good luck

 I didnt notice see any leaks but Ill watch for it next time.   

What about the piston gasket or whatever its called. If that piston gasket on the crank side is worn enough that when it draws back its sucking air, water and oil from the wash box instead of pulling concrete into the cylinder.  Could that be enough to cause significant loss of pumping volume.  Reason I ask is because when it is sitting i can see where small amounts of fluid have leaked into the cylinder from the wash box. 

All these issus seem like common ware issues  which leads me to think it was the concrete.

If the  Tee manifold is leaking, there may be residue you can see, but your lack of volume would be attributed to the air that is is sucking on the back stroke.  The hole would then plug up momentarily(with sand rock powder)on the pushing stoke. The  symtoms ive experienced are 1,2 or 3 good strokes 1 or 2 bad strokes all day long all day long.

A small amount of leakage is normal. When you start seeing slurry leaking through the backside of the pistons, change the piston cups (seals). What you describe doesn't sound bad enough to affect pumping. Your problem is probably just the concrete. A more pumpable mix will flow through the seats, around the balls and more efficiently fill the cylinder therefore pumping faster and smoother. Ball valves like good concrete.

I have a question on the Schwing P88.  I am using it to pump ICF's.  It pumped the footing great.  After we were don't we opened it up to clean it all out.  My dad decided to start it up while it was open so the cylinders would push out anything inside or them.  The largest cylinders case came forward along with pison. 

Now when we try to run it it seems to lock up and the arm on the second piston stays up in the air at times.  When it does come down it comes down hard and it very noisy. 

I will see if I can add a video tomorrow to help.

-Isaiah

I have a p88 schwing and the big arm that runs the big piston is only moving one inch. The big arm isn't touching the roller wheel  

Also I noticed he put water in the fill tank where pit on arms are. Should that be some type of oil

mechanical pumps are allways in the shop, you have to spend the money to play

The pump operators life is work all day repair the machine all night heh.

I have a p88 schwing and the big arm that runs the big piston is only moving one inch. The big arm isn't touching the roller wheel

This is the compensating piston.  It will only run when there is back pressure.  If you are running the pump dry, or with no hose, it's movement will be minimal if at all.  If you have not already done so, fill the hopper with water and attach hose.  While pumping, give the hose a quick kink.  The compensator should move then.

Also I noticed he put water in the fill tank where pit on arms are. Should that be some type of oil

I recommend an oil in the lube box.  30 weight is cheap and works.  You can run water soluble oil if you wish.  Works very well too, but may be a little more difficult to locate.  This type of pump is capable of well over 100 strokes a minute.  That is way too much for straight water to handle.  Remember, always change piston felts when chaging the type of lubricant in the box.

Whenever you first purchase this type of machine used, I would calculate in that you are going to need to replace the main wear parts right off the bat.  Purchase a 1-2-3 kit (balls, seats, cups, pins, o-rings, etc.).  Should cost around US$300.00 and everything in there you will use at some point.

Is p88 capable in shooting a pool with shotecrete  7 sac

 I've done about 10-12 pools with a mayco pump , it can be done , but , I would not recommend it , I always felt like my machine was about to explode doing it , and it is really slow , the s-tube and rock valve machine are much faster and made for that type of pumping.

Is p88 capable in shooting a pool with shotecrete  7 sac

Yes it is.  Mechanical pumps have been utilized for shotcrete for years.  Now that said, is it ideal in this day and age?  Probably not.  But if it is for the occasional job and is what you already own, it will get the job done.  They seem to find a good stride around 150' of hose and keep the pump out of the longer stroke positions.  Good clutch and belt with tight balls & seats.  Make sure your mix is right.  Maybe add some flyash for a little more cemtitious to get to 8 - 8.5 sack equivalent.

I'm working on p88..poor guy the owner.his workers left the oil cap of the wisconsin.so we have slurry in engine,water in the gas tank,back end leaking oil past the cups.....I just replaced them cups like a year ago..uugghh 

even masonary contractors will not use those boat anchors any more.