Alright, so I bought a sled with a 600 ves motor that's built into a slp 727, when I got it it wouldn't idle worth a damn and had no bottem end power, found out it had bad crank seals. I tore it down, replaced crank seals, cleaned and re seAled the cases and rejected the carbs since someone tried to bandaid the lean condition with huge pilot jets. I then got it running and same thing, runs terrible, wide open it screams but won't idle at all and loads up and dies, if you pull the choke out halfway it will idle and run better but still boggy on the bottom to mid. I then found the case halves were sucking air so I re split the cases, re sealed, let the three bond cure for 3 days, then put together and same exact problem, I then swapped fuel pumps and noticed that the fuel pump seems to lose prime while running, when revving up a bunch of bubbles appear in the inlet side fuel like at the pump and then the fuel falls back to the tank for a few seconds then catches back up again. I'm at a loss, I'm ready to sell that 727 and buy a dragon 700 and convert it to carbs if I can't get this figured out, anyone experience this before?