D311 Generator

First thing I would do is drain a sample of motor oil to check for water or metal flakes etc. Then drain fuel filter and pump it back full of fuel, bleeding air as you go. Most any industrial engine is going to have a bypass valve connected to a return to the tank which should set fuel pressure and purge any air. Sometimes pumping up the fuel pressure will reset the engine safety shutdown system and lock the rack in shutoff. The D330c powered set I had, you would hear the shutdown solenoid make a loud CLUCK WHEN this happened. There should be a reset button that would be held in or pushed in to latch before cranking to release the rack for starting

Then remove air filter pre cleaner assembly to have a flat opening to apply a small board, sturdy book etc in case the engine runs away when you start it. It's going to go straight to 1830-1860 rpm when you start it, but if it takes off for real you can quickly smother it if you are prepared.

On the generator, at least go into the connection box and look for bare wires that need taping up as well as determining what voltage it is connected for, it's connected correctly etc. If there is an exciter breaker that can be turned off or fuses that can be removed to prevent the generator building up voltage, it might be a good idea to do that until you get the engine sorted out. Be aware that the generator may build some voltage from the "residual" magnetic field remaining in the iron, but more likely this will have to be restored before it will build up even with the exciter enabled. It may have an auto-flash relay on it to do this when it runs up to synchronous rpm.

Finally look for rat nests, mud daubers, snakes etc and listen for scrubbing noises as you crank it over. It would be bad to ruin the rotor field because of a bad bearing etc. I am going to assume it will be a brush type generator since the later one we had was as well. Brushes must be free to move in holders, have good spring pressure holding them against clean sliprings. The rings don't have to be bright brass to work, but if they are, you know that isn't the problem when it won't build up voltage. There are soft stones to hold against the sliprings while the generator is spinning or you can get away with a chunk of Scotch Brite pad in a pinch. Probably best to avoid emery cloth, sand paper etc, but if you do use them, blow all the grit out of the area when you are done. You don't want any imbedded in the brushes or sliprings causing accelerated wear.

Thanks for the info. I am hoping to have a few hours to play with it this weekend. We'll see may not get to it for a month the way things are going. I ordered a manual so hopefully that will help too.

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I am curious about this part here. It seems to have 3 positions. I assume one might be shut down, one idle, and one the operating speed? It does not seem to be working properly. Any insight? Waiting for my manual to arrive.

Your Cat Gen. 51B2077 model is a D311 motor and built between 1962 -1965. 1961 serial # ended with number 1412 and 1965 year started with 3899, so some place in between is when yours was built. catskinner

Most of the engines of that era had a rack limiter plunger that would not allow the engine to speed up above a slow idle until oil pressure was up. On a wheel loader this causes the throttle to seem bound up and your engine may be the same. Once engine has started, then throttle "comes alive".

A button that pops out may have to be held in to start!

The rack limiter plunger on the ones I have seen is internal.

Ok looking at a D330 book I have it appears the big button on the end of the governor housing is pushed in to reset the rack before each start. As soon as oil pressure builds up, the button js forced back out where a detent ball and spring holds it. Low oil pressure because of lube pressure failure or because shutdown system coolant over temperature valve has opened and is bypassing oil, results in low pressure inside the shutdown unit which allows an internal spring to pull the rack to shutoff. This happens when the engine is manually shut down as well, so if the engine will start without first pushing the button in to reset the rack, the oil pressure shutdown unit is defective and needs repair to provide protection.

I cannot see any mention in this power unit book of the rack limiter mechanism I mentioned earlier, so maybe that was only applied to engines installed in machines.

are you guys sure that's a D311? I have never seen an injection pump look like that on a D311. I would say it was from the next generation of motors. very nice little genset you got