620 Carburetor Rebuild

WWS

Member
Sounds like one of the load nozzles are pluged up on my 620 since it only wants to run on one cylinder under a load unless you pull the choke about 1/4 of the way out.
I have rebuilt several carburetors in my mechanic days but never a duplex carburetor as this one is, is there any tricks to these or are they pretty straight forward?
I do have a parts book which has a good break down of the carburetor.
a19813.jpg
 
WWS, I've used that kit several times and got along well with it. However, I do not like the bowl gasket that is furnished in the kit. I go to Deere and get a "regulation" bowl gasket. This gasket works much, much better. The "kit" gasket is often too wide for the groove it fits in. Mike
 
The JD duplex carbs have drilled passages for the various circuits. There are steel balls that close the open ends of these passages.
If you have a passage partially or totally blocked, the only way I have found to totally clean it is to remove the balls. There are several tricks to remove them, none of them are foolproof.
One rebuilder uses a mig welder set low to weld an extenstion on the ball. Once that cools, they use vise grip type pliers to try to remove them.
You could luck out and just have something simple causing it to run on one.
 
You may just have a main nozzle drop out of place. I've torn a few apart that the plug fell out and the nozzle was about to. Someone before didn't tighten them.

I'd save removing any steel balls as a last resort. Good chance of ruining a carb. that may not need them removed.
After soaking in carb. cleaner overnight after I wash that off and blow them dry I put them in the solvent tank and direct the nozzle into each passage and observe for flow out the proper holes. If they flow then there open. No major sugery required.
 
Get a gasket like Mike mentioned, and more than likely that throttle shaft won't fit. The shaft is for a replacement carb that takes a bigger shaft. Haven't seen one yet, maybe it will fit yours. chris
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top