4-53 diesel runaway
4-53 diesel runaway
(OP)
I have 1966 4-53 diesel engine in a hydraulic excavator of the same year. Today when I started the engine it floored itself to full throttle and held itself there for about 20 to 30 seconds in spite of the fact that I had the throttle off. Then it dropped itself down to idle. I always push the throttle lever about 1/2 open and then back to almost closed BEFORE I press the start button (that's what is says to do in the series 53 manual). I'm thinking its either an injector that froze open and then with heat and vibration fixed itself, or the throttle mechanism on the engine itself stuck open because I never run the machine at full throttle and today I pushed the throttle lever farther foreward than usual before I started it. I don't think it is an injector because I've worked the machine hard for the two previous days and usually injectors stick after they sit for along time. On top of that the engine hums beautifully, you can hear it harmonizing with itself in perfect time. I checked the throttle cable that goes to the engine and did not see anything wrong externally. Does anyone have any ideas?





RE: 4-53 diesel runaway
RE: 4-53 diesel runaway
RE: 4-53 diesel runaway
Mike Halloran
Pembroke Pines, FL, USA
RE: 4-53 diesel runaway
Where the throttle cable attaches to the engine is a part of the engine I've never taken apart-- I don't even know what it is called. A diesel mechanic told me not to play with the govener. Can I take this thing apart and see if something is wrong in there, or will I be opening a can of worms?
RE: 4-53 diesel runaway
RE: 4-53 diesel runaway
RE: 4-53 diesel runaway
These engines are so simple compared to modern diesel and petrol engines (no common rail injection, throttle bodies, plugs, electronic pumps etc etc) they just squirt diesel into each cylinder and it runs, thats about it on an old diesel, too quick or smokey = too much fuel, no run = no fuel or timing (highly unlikely).
RE: 4-53 diesel runaway
Mike Halloran
Pembroke Pines, FL, USA
RE: 4-53 diesel runaway
You need a qualified technician to work on the governor but you can check out the throttle linkage to the governor your self.
RE: 4-53 diesel runaway
It could be drippy injectors if they only drip when the engine is warm. I only ran the engine for a minute yesterday so I don't know if a drippy injector problem would present itself today.
RE: 4-53 diesel runaway
The fuel rack, which may or may not literally be a gear rack (in this case I think it is), is what adjusts the amount of fuel that the injectors deliver per stroke.
I suppose it's possible that the rack is a little sticky in the part of its travel where it's rarely been used, or maybe a piece of debris jammed it temporarily. This would be a good time to change the lube oil if you haven't done it recently.
Mike Halloran
Pembroke Pines, FL, USA
RE: 4-53 diesel runaway
RE: 4-53 diesel runaway
Check and see if there are any grease zerks on the linkage, and if so, have they been greased since 1966? How do you kill it? Does it have an electric or air kill or do you just move the throttle to a position of zero fuel? If the latter and you left it there after the last time you killed it, I doubt dribbling fuel or fuel puddles in the engine.
My Detroits always responded a little more smartly after a good greasing of the throttle linkage.
Did you notice anything unusual about the exhaust when this excursion occurred? If there were a lot of unburned fuel present, or lube oil being burned, your exhaust would indicate it. My last Detroit would lay down a smoke screen as it burned all the oil that puddled inside the engine (from the myriad of places that a Detriot can find to leak, internally and externally.)
The detroits I dealt with were air killed and until air built up enough pressure to activate the air solenoids (pistons) hitting the kill switch wouldn't kill it.
Now, a trip of the engine combustion air valve would, however and in a hurry.
And, NO, NO, NO, don't touch the inside of the governor housing, or any of the external settings. Guys that can do that are getting rarer and rarer, now that electronic engines are in vogue. Even when the old rack system was king, the guy who could do it and do it right was rare too.
rmw
RE: 4-53 diesel runaway
RE: 4-53 diesel runaway