68Datsun510 Posted June 18, 2009 Report Share Posted June 18, 2009 Hey folks, i recently picked up an 82 720 4x4 for use as my wood truck/snow truck. I live at 4000feet and 4wd is a necessity. Anyway, I was in the middle prepping the engine for a full tune up, all flexible hoses, all ignition bits, and clean up the carb when after i removed the carb, the "spraybar" for the secondary just fell out onto the floor. I noticed that even in hot weather the choke stayed shut as well. I have never disassembled this sort of carb before, I have torn a DCH 340 apart, but i cant use that on this because I have to pass CA smog. It has a DCR 342. Any tips on how to fix the spraybar? ANyone have a good cond 342 to sell??? Quote Link to comment
datzenmike Posted June 19, 2009 Report Share Posted June 19, 2009 Spray bar? Do you mean the secondary venturi? Aren't the California ones staked and not removable? Got pictures of it? Quote Link to comment
68Datsun510 Posted June 19, 2009 Author Report Share Posted June 19, 2009 Heres the pics. Quote Link to comment
datzenmike Posted June 19, 2009 Report Share Posted June 19, 2009 There is a set screw that holds and locks both the primary and secondary venturies in position. Remove the secondary operating vacuum diaphragm: http://i138.photobucket.com/albums/q251/datzenmike/720%20stuff/720carbsecondaryventurisetscrew0012.jpg[/img]"] Behind it you should see a set screw that threads into the back and locks the venturi in place. Over to the right you can see the one for the primary venturi: http://i138.photobucket.com/albums/q251/datzenmike/720%20stuff/720carbsecondaryventurisetscrew0011.jpg[/img]"] Carb may have been previously re-built. The screw may be loose or missing. Pretty sure later Cali carbs venturies are not removable. Quote Link to comment
68Datsun510 Posted June 20, 2009 Author Report Share Posted June 20, 2009 ALready have it torn down to that part, it definitely has never been rebuilt, varnish abound. ALso, how the hell do i get those setscrews out? Tried every size flathead and they all come away damaging them. I hit them with some pb blaster and will check on them tomorrow. I am "berrymans Chem-DIp" -ing every part as i remove it. This thing should run like a top when I am done with it! Quote Link to comment
68Datsun510 Posted June 20, 2009 Author Report Share Posted June 20, 2009 One more thing, on the vacuum secondary module, if i depress the secondary actuator arm upwards into the canister, then block the hole with my finger, should it rebound as if i hadnt covered the hole? I tore it down and inspected it, no damage found, totally intact diaphragm. Quote Link to comment
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