BeachKidd Posted April 11, 2015 Report Share Posted April 11, 2015 I have a 78' 620 king cab with an l20B and just installed a new weber 32/36 DGEV carb with electric choke. When I went to start the truck cold the idle seemed higher than it usually did with the stock carb and electric choke and it also wont kick down. Im new to this kind of stuff and all the help I can get is appreciated! Quote Link to comment
ggzilla Posted April 11, 2015 Report Share Posted April 11, 2015 Fast idle should be 2400 rpm. It won't kick down to slow idle until warm I've found setting the fast idle to 1600 works good. Just turn the fast idle screw. Quote Link to comment
BeachKidd Posted April 11, 2015 Author Report Share Posted April 11, 2015 Okay I will try this. I don't have a tach but it sounds like its revving around 2500rpm. Should I turn the fast idle screw in or out ? Quote Link to comment
ggzilla Posted April 12, 2015 Report Share Posted April 12, 2015 Yes Or just leave it be. It should run fine at the high factory fast idle speed. Quote Link to comment
BeachKidd Posted April 12, 2015 Author Report Share Posted April 12, 2015 The idle just sounds way too high and trying to kick it down makes it even worse. Quote Link to comment
datzenmike Posted April 12, 2015 Report Share Posted April 12, 2015 High idle causes... Fast idle set too high. Idle speed screw too far in. Choke not shutting off or set too rich. Electric choke should have power when engine running. Throttle cable or linkage not adjusted properly Secondary stuck or not closing Primary stuck or not closing. Quote Link to comment
BeachKidd Posted April 12, 2015 Author Report Share Posted April 12, 2015 I believe the choke opened up, but I've only tighten the fast idle screw haven't tried to loosen it up yet. Linkage for throttle looks good and everything is opening up Quote Link to comment
ggzilla Posted April 12, 2015 Report Share Posted April 12, 2015 Read the Datsun factory service manual. It is supposed to be very high. I prefer it set lower so it is quieter. Quote Link to comment
BeachKidd Posted April 12, 2015 Author Report Share Posted April 12, 2015 Update: the top butterfly's were completely open I held the almost all the way closed and it sounded like the cold start idle I used to have at around 2000 rpms Quote Link to comment
ggzilla Posted April 12, 2015 Report Share Posted April 12, 2015 There is no fast idle when the choke (top butterflies) are completely open. Just the regular idle. Sounds like it needs adjusting rather than tuning. After installing a new carb, always adjust the choke, then after warming the engine fully adjust the idle speed and idle mixture. Fast Idle only comes into play when the chokes are closed or partially closed. Quote Link to comment
BeachKidd Posted April 12, 2015 Author Report Share Posted April 12, 2015 Thanks ggzilla, I will adjust the choke in the morning and see how it goes. I appreciate the help Quote Link to comment
BeachKidd Posted April 12, 2015 Author Report Share Posted April 12, 2015 Update: I resolved all issues. Thanks for the help! 2 Quote Link to comment
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