I was pumping with my 2002 schwing 750-18x and we got about 6 yards into it and the pump started to stuter and almost die but never did. It would only do this when the rock valve would swing and it would run fine on the stroke. I got the job finished and washed out and it still did it. When i got back to the shop to work on it we couldnt get it to stuter anymore.  So i went on to do 5 more jobs fine no problem, now i had a job yesterday and it started acting up again. Any input would be appreciated

my was doing some weird stuff and last falls freeze took out my fuel pump.

For me,I believe I would start looking at the simple stuff.Fuel filter,air filter,might even go as far as thinking fuel tank contamination.Beyond that call Rodger.

If your saying it would only do it on the shift is telling me that when a massive loads is on the truck it stutters. Check underneath the valve for debrey or built up concrete. The truck has just as much load on it shifting the valve as it does stroking. So if it were filters or fuel, air, etc. it would wanna die after any load was put on it. Check your accumulator pressure and is it in hard stroke or soft. Start looking at anything that has to do with it shifting. Good LUck and post your results so that others may learn. PUMP ON.

Thank you for the quick post. I did check the air filter and changed the fuel filter and i thought maybe it could be the fuel pump. I check the accumulator gauge when it was stuttering and have good maintained pressure and the pump pressure didnt change at all when it would stutter. I thought it could be hydraulic pump or something similar, but you would think it would make the pump stuter all the time not just half the time or not at all. It seems to me that the vibration from the rock valve swinging is making something fail.

GetRdone I dont think my pump has the hard or soft stroke adjustment but I could be mistaken.

eugene what pump do you have that had the similar problems and what were the symptoms?

Check the little fuel filter screen, theres a phillips head screw to take it off. It's round, sorry I can't explain where it is better.

check your voltages sounds like a electric issue to me not a fuel or air ,

Does it have a Nitrogen bladder ? If it does then hit an e-stop and watch you accumulator pressure guage. If your bladder is ok the perssure will gradually go down to around 80 bar, and then drop to zero. But if it goes below 80 bar before it drops the you might need a nitrogen charge. Or maybe a blown bladder

But I dont know, i'm just an operator

The nitrogen bladder is fine there is plenty of precharged pressure. I pumped again with it today and it did the same thing. It seems to be worse if I run it at lower rpms like 1500 to 1700 but if I run it closer to 2000 rpms its not vary noticeable. It only starts to do it after about 5 yards so it only does it when the pump is warm, but I couldnt get it to do it when i washed out the hopper.

I think i need a schwing mechanic.

hey 440 i have a 2006 tk-40 72 hp turbo. taked to the factory rep in california that i bought it from and told him about the quirk, he told me they had some but did not know why. my issue happed years later at 900 hours.

take the fuel pickup line out of the fuel tank, should be a brass tube with a screen at the bottom. Check for buildup on that screen.

Grease ??

Well I worked on it all day checked the lift pump plenty of fuel pressure, changed the mudcups becuase I was working on it already, checked the electrical system, and I grease the pump at least once a week. I guess ill have to just take it to a mechanic. I appreciate all of you help this site helped me out alot. thank you

sounds to me that there is some trash floating in your hyd. system, what does the oil look like? filter elements? have you ever drained the oil out and cleand the hyd. tank?

Since you changed the fuel filter, thats not it. I would guess an obstruction on the switching cylinder and rock valve. The shut off "in line valve" isn't half cocked is it? Or grout build up in the bushings or worn sticking rock valve bushings worn causing resistance. Try calling Schwing service advice 1651-429-0999 ask for tech support. They'll know.

I changed all 70 gallons of the hydraulic oil and filter and put in fresh 150 hours ago. I chipped all the concrete out from under the rock valve. The pump still pumps concrete fine, and the concrete doesnt seem to slow down at the end of the hose.  The motor will just stutter for a split second after the swing of the rock valve and it doesnt do it on every swing, and will be fine for a couple of strokes.

I have a BPA 500. It did the same thing and got worse as I kept using it. I took it in to a Diesel shop that worked on deutz motors. They informed me the motor was dusted. Which meant it needed to be rebuilt. Hard lesson learned for not changing the air filter enough. If you pull the dip stick out while it is running and notice oil blowing out of the hole it could have the same problem. It still ran fine without a load. It did the sputtering or loss of RPM's while the motor was loaded or pumping. Good luck, hopefully yours is a much simpler problem.

hey bud only doing it at end of stroke when signal is sent to manifold to create your change over you will find looking at your concrete cylinders pressure gauge you will be getting a large spike on change over loading up motor. Theres nothing wrong with your motor just a signal problem 

change the filters and see what it dse or could but the h fuild

Were you pumping on a hill or incline? My 2003 Putz TK-40 does that when tilted...sometimes even just a slight tilt. I think it has a low oil safety shut-off. I put blocks under low wheel to reduce tilt andit runs fine.

steadyeddy is on the right track. If the engine is trying to stall during the shift, there is an extra 20HP being drawn out of the engine. The fuel tanks had a screen installed on the draw tube of the fuel tank on earlier versions. Remove the tube and check. Also, try swapping the 2 fuel hoses.And make sure that the fuel caps are vented.

The Deutz engines have overfill hoses on the top that are connected to the fuel return line. If they are leaking, they could also be sucking air. Look for white smoke. This would make the engine hard to start also.

I had this exact problem start on my 04 schwing 305. I believe I figured it out. The motor was fluttering under stress. I shook the e stop and it stopped for a while then started again so I took the switch out and checked. The screws and wires were rusted. So I bypassed the switch (between rm trucks) and the problem stopped. It was loosing continuity. Why only under stress? I don't know, but probably the start of total failure.

I had this exact problem start on my 04 schwing 305. I believe I figured it out. The motor was fluttering under stress. I shook the e stop and it stopped for a while then started again so I took the switch out and checked. The screws and wires were rusted. So I bypassed the switch (between rm trucks) and the problem stopped. It was loosing continuity. Why only under stress? I don't know, but probably the start of total failure.