Engine will violently shut down. Suspected hydraulic fluid overfilled. Bought machine from person that apparently attempted to repair several things without a manual and/or the knowledge needed. Overfilling the system was probably one of his mistakes. Weather has prevented further work on machine. My question is "Does the violent shut down of the engine imply the possibility of an overfilled hydraulic tank?" The sight glass, according to a retired operator of 973's and a tenant in my RV park, is full to the top. I would hope I can drain down and observe a proper fill after weather clears up. Am I on the right track?
You'd better find out what was the "several things" they repaired, and what they actually did, without a manual, before you can diagnose further. Never heard of a "violent shut down" caused by an overfilled hydraulic tank before - but I've never run across a hydraulic system that has been filled to the top, either. If someone worked on it, who didn't even understand what an oil level sight gauge is, or what it's there for, then anything is possible. The violent shutdown sounds to me, more like that unskilled person installed some hydrostatic transmission hoses wrong and the oil is going the wrong way, causing a hydrostatic system lockup. Is the transmission still operating correctly when the engine suffers its "violent shut down"?
Thanks for the response. I don't operate the machine, my son does. I will get with him to respond to your question about the transmission. We have the manual, and it was purchased to guide in the rebuild of the right-side undercarriage. That went very well with the assistance of Holt Cat technical support. Would the machine still operate for 15 minutes if hoses were improperly installed? Thanks again.
Yes, I've had a complete new power steering installed on a Mack truck with hoses incorrectly connected (due to inadequate manufacturer installation advice), and it steered well on a 15 minute drive - before it completely locked up the steering, and we ran off the road!
I discussed the problem with my son and I guess I misunderstood him. He says he didn't call it a violent shutdown. He now described it as after 15 minutes there is a gradual slowing down and the engine would quit. After about 5 minutes was able to start back up. Sorry for that. What do you think. Still possibly improper hose installation?
Has anyone looked at the screens/filters in the fuel system for the presence of water or dirt.? The same question would also apply to blocked fuel lines or the presence of water/dirt in the fuel tank. Another thought. When the engine starts to act up after 15 minutes of running, unscrew/remove the fuel cap.? Does that change anything.? Do you have any manuals, especially parts, for this machine.?
Sound to me like a fuel supply restriction problem, Nige is onto it. Unscrew the fuel line from the tank just before the injection pump and see what the fuel flow is like. I'm not 100% familiar with the 973 setup (although I drove one for several months), but the fuel system has a primary screen, and then a screw-on fuel filter. You would need the books to be able to locate the position and identify the fuel screen. Sometimes the primary screen is below the fuel tank, most times it's just before the fuel transfer pump, which is just before the fuel filter. Make sure the primary screen is taken out and cleaned, ensure the outlet from the fuel tank isn't partially blocked (they can get blocked with an accumulation of dirt, fluff from rags, corrosion flakes from moisture, and even muddy water), and that fuel flow is strong. And check that the breather hole in the fuel cap isn't blocked.
If fuel is Low enough try pulling the fill screen and see if something is floating around in there.
I'm thinking fuel issue too
Could always take the fuel line off before the fuel filters and take the fuel cap off, blow with compressed air back into the tank. If it builds any kind of pressure on the line itself there's a blockage or kinked hose. If the internals of the hose is damaged and is blocking you can also try put a pump on the line and see what the fuel flow is like. On my 3306 on my 973 the main intake screen is located in a canister just before the fuel filter. Which you can remove and check the screen. While the engine is slowing down, if he put it back to low idle would it recover, or would it still die? Sounds like the injection pump is creating a vacuum on the fuel system and once it can't pull anymore fuel due to the vacuum it starves itself.
Silence from poster, Hmmm
I was thinking that as well.
Maybe getting the tractor operational isn't a priority for him, right now. Or maybe there's a communication glitch between him and his son, as it's not his tractor, anyway.