a.d._510_n_ok Posted November 15, 2009 Report Share Posted November 15, 2009 I've got 99% of my carb issues worked out but the little sucker idles way too high when first started. When it gets warm it runs just the way I want it to. What do I need to adjust to get my cold idle turned down a couple 100 rpms but not alter anything else? I got the Chilton on the thing - just wanna be sure I'm adjusting the right thing. Quote Link to comment
datzenmike Posted November 15, 2009 Report Share Posted November 15, 2009 When started up cold the choke will be on to enrich the mixture. Running rich will require more air so there is a stepped cam with adjusting screw to let more air in when the choke is on. It's only reasonable that the RPMs will be higher on initial start up. It might be fine you just may think there's a problem. With carb off engine, set the fast idle cam on the first step. On the under side of the carb, measure the small opening between the throttle butterfly and the carb wall. It should measure 0.052" to 0.058" for manual trans and 0.062" to 0.068" automatic. The adjustment screw is pictured below and is hard to get at with carb on engine. It's likely fine so check the paragraph below the picture... http://i138.photobucket.com/albums/q251/datzenmike/720%20stuff/carbZ24fastidleadjustLg.jpg[/img]"] Warm the engine up thoroughly and set the cam on the second step. The engine should rev between 1,900 and 2,800 RPMs. Quote Link to comment
ggzilla Posted November 15, 2009 Report Share Posted November 15, 2009 Stock Datsun specs for fast idle are in excess of 2000 RPM. So it won't hurt anything to "run fast". I like to set it at 1600 RPM only so that it is quieter. Quote Link to comment
bonvo Posted November 15, 2009 Report Share Posted November 15, 2009 having run the hitachi for 4 years i can tell you i hate that carb with a passion but fast idle mike is right on the money as always Quote Link to comment
a.d._510_n_ok Posted November 16, 2009 Author Report Share Posted November 16, 2009 Stock Datsun specs for fast idle are in excess of 2000 RPM. So it won't hurt anything to "run fast". I like to set it at 1600 RPM only so that it is quieter. well, hell, little carb is dead on I reckon. at 2100 cold it sure seems fast to me but if ya'll are tellin' me it's within spec I ain't a-touchin' it :lol:! honestly, after I got all the rotted vacuum lines swapped out I haven't had any troubles with the Hitachi. I keep a clean air filter on top of it, clean fuel filter in front of it, Shell 91 + Marvel Mystery Oil going into it and never have any problems with it. Quote Link to comment
RatVonDude Posted March 11, 2016 Report Share Posted March 11, 2016 well, hell, little carb is dead on I reckon. at 2100 cold it sure seems fast to me but if ya'll are tellin' me it's within spec I ain't a-touchin' it ! honestly, after I got all the rotted vacuum lines swapped out I haven't had any troubles with the Hitachi. I keep a clean air filter on top of it, clean fuel filter in front of it, Shell 91 + Marvel Mystery Oil going into it and never have any problems with it. Having the same issue. Would really like to convert to manuel choke. If possible. Not sure how the smog check people are about swapping carbs, but i kinda wanna ditch the hitachi. 1 Quote Link to comment
throw1932 Posted March 17, 2021 Report Share Posted March 17, 2021 bringing this back up to try and get an answer on an issue with my carb. the throttle arm that depresses the accelerator pump is at an angle, I am not sure if there is supposed to be a washer or something, or if mine is just really worn. it forces the plunger to sit at a slight angle, and the linkage occasionally gets hung up on the oil breather tube. throttle closed throttle wide open difficult to see, but it is cocked over a bit Quote Link to comment
datzenmike Posted March 17, 2021 Report Share Posted March 17, 2021 Try a thicker washer. Quote Link to comment
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