Jump to content

Hitachi carb high idle ???


Recommended Posts

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.

Link to comment
  • Replies 7
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

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]"]carbZ24fastidleadjustLg.jpg

 

Warm the engine up thoroughly and set the cam on the second step. The engine should rev between 1,900 and 2,800 RPMs.

Link to comment
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.

Link to comment
  • 6 years later...

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 laugh.gif!

 

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.

  • Like 1
Link to comment
  • 5 years later...

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. 

 

20210316094057.jpg

throttle closed 

 

20210316094025.jpg

throttle wide open

 

20210316093923.jpg

difficult to see, but it is cocked over a bit

Link to comment

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.