Cat 12 grader not starting?

Spray everything down with penetrating oil and then move throttle lever rather vigorously so you are sure it is not stuck in the shutoff position.

Then you can pry the plungers up and back down to break them free in the pump bores. Also gently pry the rack back and forth while spraying the bearings. Its best to work on the individual plungers first before prying the rack so you don't inadvertently move the quadrant gear on a stuck plunger. Probably not easy to do, but possible never the less.

Also make sure the decompression lever is in the run position, not start. I purchased a 212 that the previous owner couldn't start because he didn't understand about the decompression control. It was a good thing because it had no oil pressure when I got it turning over.

Good luck

Add oil to the hex/slotted plug threaded into the pump housing below the inspection cover you removed for the rack picture. Use the same oil you use in engine, 30 wt, 15W40 etc and fill until oil level is in the filler neck, just not quite running over. That sump is shared with the governor compartment on the back end and primarily lubricates the camshaft and lifters that operate the injection pumps. The actual governor flyweights in the D4600 4.25" bore 6 cylinder engine are in the front timing gear area and the force generated is transmitted through the rack to the springs in the rear compartment with the high and low idle stop adjustment screws on top.

The upper compartment of the injection pump housing containing the pumps is essentially fuel lubricated. The plungers are very closely matched to their respective pumps and if in decent condition will leak only a tiny amount of fuel which is shed into a gutter drained by a drip line routed forward and down along the left front corner of the engine block. If this line is crimped or plugged (to stop the drips), the fuel accumulates and dilutes the oil in the sump.

Get the serial number and we can tell you the year of manufacture of the grader. Engine serial number would have originally matched the chasis serial number usually found on the frame forward of the cab somewhere.

Simplest way is to move decompression lever back to start position.

Air restriction is another way as long as you don't have any leaks in the intake system. Sometimes the heat exchanger between pony exhaust and diesel intake is cracked which would make choking it down a lot harder.

If you are pulling it, you can likely control a runaway by letting out the clutch in one of the higher gears you will probably be starting it in.

Aahhh, governor flyweights are in the governor itself on the D4600. You can see them in the picture with the rear governor cover off.

Sounds good I will let you know how it turns out tomorrow

Does the D4600 narrow it down as far as years or is that a better or worse design or just an observation?

Thanks you again

Jamie

The 9T series with D4600 was produced from 1938 to 1945.

With a little penetrating fluid and a little persuasion the old girl came to life😃 the rack was stuck the plungers seemed ok

Thank you all for your time and expertise

Jamie

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