I just pumped 32 yards of 3000psi grout 1000 feet with 2.5" hose.  Woke up at 1:30am thinking of how to prime that much hose then worried about how to clean that much without plugging.  Primed out and cleaned out without any issues.  Looked like I knew what I was doing.  My little Olin 5-60 pushed it with no trouble, slow but great.  For the prime I pumped water and let it sit in the hose for 30 minutes.  Then drained as much as I could.  Poured 3 gallons of bentonite into the hose and inserted saturated bentonite news paper in the hose.  Put my water as normal into hopper and started pumping.  Got scared as pressure climbed thinking it was about to plug but I slowed the volume down and it just kept going.  The grout had anti wash out admixture in it so it was sticker as molasses.  The engine was about half throttle and volume about 1/3rd, any faster the pressure would climb and I figured why, it's pumping.  Clean out I pumped some water then went to the 300' section and broke loose.  Pumped until clean water came out Installed paper and re connected and repeated at 600 feet then kept going until paper came out at the 1000 foot end.  I had a 3" water line filling the hopper so clean out was fast.  It was a challenge and a feat for me but if I never do it again I am ok with that.