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jdemaris
06-25-2006 06:52:05
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Re: JD450 cdc pump question in reply to motorhead460, 06-24-2006 17:53:26
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The CDC is a fairly reliable pump, although it was rendered obsolete back in 60s and replaced with a the better CBC model. The CBC was dropped late 60s and parts for all the Cs were, more-or-less discontinued around 1980. The CDC was subject to MANY updates. It has just about as many parts to fail as a DB or a JDB - except there is no plastic weight retainer ring to fail. CDC rack and pinion throttle gears tend to wear out as well as the transfer pump blades. I'm not sure what you mean by a "metering valve" in the DB return line. The metering valve is what operates the throttle in the DB or JDB and is no where near the fuel outlet. Perhaps you are referring to the housing pressure regulator - which screws into the top cover and has a little spring and ball in it? The CDC also has a housing pressure regulator, but it's inside the pump. The DB or JDB uses a metering valve that rotates back and forth and is hooked to the throttle linkage, whereas the CDC metering valve is a plunger that is pushed back and forth inside a tube - by the throttle rack and pinion gears. First thing I'd check on your CDC is the advance timing. You need a timing window for for that - it's a little round one with circular degree lines # 17180. Fuel timing advance is often the first thing to wear out, or get sluggish. The original CDCs had many problems associated with cold starting, engine idling, engine smoking, no load skipping, etc. and these issues were corrected with updated parts. Considering you pump is 40 plus years old - it may of already been updated, but perhaps not. I know of many tractors with CBC pumps that have never been touched since new. The CDC pumps, however, mostly got fixed or replaced. Deere was selling change-over kits for them staring in the late 70s - to change over to the JDB pumps. Kit came with a brand new pump, driveshaft, drivegear, injector lines, etc. and had around a $800 price tag at that time.
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