Jet_reference.JPG;|||P1080733.JPG;2 Gold on left = air correctors, sitting on emulsion tube and main jet|||P1080748.JPG;|||P1080749.JPG;|||P1080750.JPG;|||P1080751.JPG;Not sure why this paperwork says 40 DCNF. I definately have a 42 DCNF. Wrong paperwork included?|||P1090541.JPG;|||P1090549.JPG;Butterfly valves pre-drilled with holes. As result, I can't get idle below 2k RPM. Need replacements|||P1090550.JPG;78 degree valves|||P1090551.JPG;Center spring loaded screw = idle speed screw (aka throttle stop screw)|||P1090552.JPG;one silver slotted air bypass screw barley visible behind the choke|||P1090553.JPG;42 DCNF 9 1D stamped on side of float bowl|||P1090556.JPG;choke assembly shown in the center|||P1090558.JPG;enrichment pump on left and throttle zip stripped on the right|||P1090781.JPG;manual choke cable fitted|||P1090794.JPG;|||P1090810.JPG;|||P1090816.JPG;|||P1090818.JPG;|||P1090819.JPG;|||P1090820.JPG;|||P1090822.JPG;|||P1090825.JPG;|||P1100041.JPG;|||P1100042.JPG;|||P1100043.JPG;|||P1100044.JPG;|||P1100045.JPG;|||P1100046.JPG;|||P1100047.JPG;|||P1100048.JPG;|||P1100049.JPG;|||P1100050.JPG;|||P1100051.JPG;|||P1100052.JPG;|||P1100053.JPG;|||P1100054.JPG;|||P1100056.JPG;|||P1100058.JPG;|||P1100059.JPG;|||P1100060.JPG;|||P1100062.JPG;|||P1100063.JPG;|||P1100064.JPG;|||P1100065.JPG;|||_jet_reference.JPG;|||_jet_reference.jpg;|||jet_reference.jpg;|||AlbumDescription;<p>This is a collection of pictures and information regarding the Weber carburetor supplied as part of the MSS induction kit.</p>
<p><strong>Weber 42 DCNF 9 1D,</strong> made in Italy<strong><br /></strong></p>
<p>Jets and sizes provided by MSS<strong>:</strong></p>
<div>
<ul>
<li>Venturis = 32 mm</li>
<li>Auxillary Ventirui = 4.5</li>
<li>Main Jet = 160</li>
<li>Idle Jet = 0.93</li>
<li>Emulsion Tube = F24</li>
<li>Air Corrector = 180 </li>
<li>Pump Jet = 75</li>
<li>Back Bleed = 1.20 (maybe 120)</li>
<li>Needle Valve = 175 </li>
<li>Fload Level = 52/58.5</li>
<li>Starter Jet = 1.10F7 (maybe 110 F7)</li>
<li>Accel &amp; Cam = 42</li>
<li>Transition Holes = 50-53-55-56</li>
<li>Throttle Disc Bleed = 2.35</li>
</ul>
<div>Here is a list of adjustements I made to get my car running correctly. Note, I am at about 5000 feet of elevation.</div>
<div><ol>
<li>Main jets changed to 140 and 145 (down from 160).</li>
</ol>
<div>Useful background information copied from other Internet sources:</div>
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<div><strong><span style="color: red; font-size: large;">Idle jet</span></strong> <br /> 
<ul>
<li> There are 2 idle jets per carb, one per throat. Each jet acts totally independent of the  other.</li>
<li>Located under the screw in the photo is one of the idle jets. It is  nothing more than a brass tube with a calibrated hole in it. These jets  are available with larger or smaller holes depending on the amount of  fuel you wish to introduce to the engine<strong>.</strong></li>
<li><strong>Contrary to its name&nbsp;the idle jet supplies fuel to the engine  up to about 3000 rpm so it is a vital part of the tuning equation.</strong> This will keep coming up so be clear on this point</li>
</ul>
</div>
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</div>
<div><span style="color: red; font-size: large;"><strong>Idle mixture adjustment screw</strong></span><br /> 
<ul>
<li>Again there are two of these which act independently on each throat of the carburetor.</li>
<li>These screws can be adjusted down all the way to fully closed where no fuel gets to the engine during idle.</li>
<li><strong>The adjustment of these screws are to be used&nbsp;ONLY to adjust  the mixture at idle! Mechanics often turn these to correct low speed  running&nbsp;problems and this is totally wrong. The idle screws are for idle  ONLY.</strong> </li>
</ul>
</div>
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&nbsp; <span style="color: red; font-size: large;"><strong>Air bypass screws</strong></span><br /> 
<ul>
<li>One per throat</li>
<li>Allows for a compensation between throats of a single carburetor to equalize the flow between the two barrels.</li>
<li>When properly adjusted, one of the air bypass screws is closed while  the other is open a measured amount. We will discuss this setting later  but if both are open the carb is not set correctly. In some instances  both may be closed but for both to be open is not correct. </li>
</ul>
<hr />
<strong><span style="color: red; font-size: large;">Idle speed screw</span></strong><br /> 
<ul>
<li>Because the each carb has only one throttle shaft that operates both  throttle butterflies there is only one speed screw per carb.</li>
<li>Think of the throttle butterflies as doors that allow the air/fuel  mixture to enter the engine and the idle speed screw is a stop that  controls how much the door closes. Because the engine needs a certain  amount of air/fuel mixture in order to idle, the speed screw allows for a  fine adjustment of how close to closed the butterflies are and is  essential in setting the idle speed of the engine.</li>
<li>The idle speed screw is one of the most tinkered with screws on the  carb and is often opened far too much. Generally speaking if the screw is in&nbsp;more than 1.5 turns from the moment it contacts the throttle then it is turned too far.</li>
</ul>
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<hr />
<strong><span style="color: red; font-size: large;">Summary</span></strong><br />
<ul>
<li>Idle jets control the engine up to about 3000 RPM</li>
<li>Idle mixture adjustment screws are to control idle only</li>
<li>When properly set only one (or neither) of the air bypass screws are open; not both.</li>
<li>Idle speed screw is used to set idle speed only and should be kept between about 1-1.5 turns from the first point of contact.&nbsp;</li>
</ul>
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</div>
</div>
<ul>
</ul>
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<ol> </ol></div>
<ul>
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