I have a high hour (3700hrs) Cat 305C CR machine. It's a 2007 and recently I was running it helping my friend put in a driveway and doing some land clearing. Today when I started the machine, very little power. In fact as soon as I engaged the hydraulic activation lever, the engine bogged down about 1/2 RPMs and engine started smoking. Now this machine does have blowby and the engine will need a rebuild, but it generally works and typically doesn't smoke that bad. I do burn 1 quart of motor oil about every 65-70 hours. One day, I will get to a rebuild. But this problem is new - motor bog only when hydraulics are turned on. And also my left track has no power. All hydraulics are very slow, but I noticed if I consistently swing the boom back in forth, I restore all hydraulic power while that boom is swinging. This is what I did to drive the machine back to my trailer and load it. It feels like maybe a valve issue and that swinging the boom is what allowed the hydraulic to bypass or relief. Also my blade has full hydraulic power the whole time and can lift machine to max height but boom/dipper, no power. Boom/Dipper very slow movement. Left track slow movement, right track normal. Left track running fine if I operate the swing circuit. Very weird, but I know this must mean something to someone familiar with these. Thanks, Michael
A Serial Number would be a good start. That sounds like the classis symptoms of a dodgy resolver valve somewhere in the controls.