Jump to content

Hesitation upon accelerating from a stop


jboulukos

Recommended Posts

  • Replies 103
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Will do, thanks for the great advice.  I have looked over the Hitachi Rebuild post in the "How to" section.  I want to post questions as they come up.

Here we go...

Is there a way to tell what year the carb is from/what model car, etc...?  Were there different carbs for automatic versus manual trans?   

  • Like 1
Link to comment

do the ez stuff first.

Ck the timming.

replace the fuel filters

 

Clean the shit out of the carb.

 

My 521 idle jet just plugged up. like multiple times while checking it out. I got some canned air and cleaned out the  idle circuit by sticking the strw right in the idle jet holder. Then replaced the filters and saw thay more fuel was going thru now. Not that the filter was overly bad. otherwise I would not go the speed limit if it was really plugged up.

 

Going to a weber is the ezest solution if anything. the stock carbs are a time bomb waiting to happen with the small bearings ect....in there.

 

if you got compression then this has nothint to do with acceleration.(my opinion)

 

4500$ that guy is fucked. Fix this and take it back to him!!!!!!!!!!say Im going to post this on the internet how much you guys suck.

  • Like 2
Link to comment

On the larger Hitachis like the 340, there are numbers etched or printed (not stamped into the metal) on one side of the float bowl body. I suspect this is also true with the smaller Hitachis, but don't know for sure. The first pic here may be a clue: http://datsun1200.com/modules/mediawiki/index.php?title=Carburetor_Specifications

Try cleaning the flat surfaces on the carb body really well and see what you can find. The numbers aren't at all easy to see. Shining a light at an angle from one side sometimes makes them visible.

 

There may be an online list of how these number relate to models and years, but I don't know where. You might try a Google search. The factory service manuals under carb specs probably list the carbs used for a particular year and model. Here is a recently posted link to many FSMs:

 

http://community.ratsun.net/topic/69391-service-manuals/?do=findComment&comment=1380843

 

If you can find a master list of carbs to year and model it would be much easier than going through multiple FSMs.

 

Len

  • Like 1
Link to comment

do the ez stuff first.

Ck the timming.

replace the fuel filters

 

Clean the shit out of the carb.

 

My 521 idle jet just plgedd up. like multiple times whele cheacking it out. I got seme canned air and cleaned out the  idle circuit by sticking the strw right in the idle jet holder. Then replaced the filters and saw thay more fuel was going thru now. Not that the filter was overly bad. otherwise I would not go the speed limit if it was really plugged up.

 

Going to a weber is the ezest solution if anything. the stock carbs are a time bomb waiting to happen with the small bearings ext in there.

 

if you got compression then this has nothint to do with acceleration.(my opinion)

 

4500$ that guy is fucked. Fix this and take it back to him!!!!!!!!!!say Im going to post this on the internet how much you guys suck.

Thanks!  and Agreed on the mechanic comment.  I look at it like this...  

 

That guy charging $250 for some basic compression/leak down/pressure testing and then a $4500 quote with refusal to do the head gasket without full rebuild   

Plus

Awesome Ratsun encouragement and problem solving through forum questions and responses

Equals

my change in thought processes towards auto mechanics and a closer more meaningful connection to my B-210.  

 

So, I am thankful for the mechanic because it lit a fire under my ass.  

 

Some questions on your input...

-where are the filters you replaced located?

-where is the idle circuit you are referring to?

Link to comment

here's the obvious tags on each carb.  I found some faint numbers etched on one but not legible.  There are different types according to the '78 Service Manual but I am uncertain where to locate a "DCH" number on the carbs.

 

image_3.jpeg

image_4.jpeg

image_5.jpeg

image_7.jpeg

  • Like 1
Link to comment

Here's the 3 extra carbs I grabbed from a part-out.  They look pretty crispy.  Is it worth choosing the cleanest one and rebuilding it?  The one on the right seems clean.

Thinking about putting some Pink Floyd on the turntable and getting at it.  I have a carb rebuild kit as well.  Any suggestions? things to avoid?  things to be careful of?  

 

 

 

Umma Gumma... avoid that, and pretty much everything before DSOTM although Meddle is worth a listen. Then everything through The Wall and The Final Cut. And that's about it.

 

  • Like 1
Link to comment

Yeah, those faint numbers you found, if one the carb body, are probably the DCH numbers. Try looking at them outside in brighter light. But sometimes they are pretty illegible. I suspect the main differences between the different carb numbers are the sizes of the jets and emulsion tubes. Unless you need to pass a smog test, you might look at your carbs and find the largest jets you have and go with those. I'm not sure how much they need to be matched to the air bleeds and emulsion tubes and all those other little thingies. Farther down one of the pages I linked to before it a table of sizes:

http://datsun1200.com/modules/mediawiki/index.php?title=Carburetor_Specifications

 

I had this page Bookmarked: http://www.mazdabg.com/ftp-uploads/Mazda/929/Mazda%20Carburetor%20Training%20Manual.pdf

Hope I don't get banned from Ratsun for posting a link to Mazda lit :P , but it gives a good explanation of the different carb circuits. Datsun FSMs have something similar, but these Mazda pages highlight the circuits in red which makes them easier to follow. Probably just enough differences between these drawings and an actual Datsun carb to be confusing.

 

Len

  • Like 1
Link to comment

IMG_5154.jpg

 

Picked up this tune up test kit today.  

A few questions...

1. Is the '78 B210 a positive ground vehicle or negative ground vehicle.  This effects how the dwell/tachometer leads will be set up.

2. When adjusting the idle, this is done by turning the idle adjusting screw on the carb, with the dwell/tachometer set up on ignition coil?

Link to comment

1. Negative ground

2. Yes.

3. Yes, no mechanical points, no dwell to set

 

Thank you.  Going back to question 3.  So timing is adjusted by loosening the distributor set screw and moving the distributor before locking the screw in place? 

  • Like 1
Link to comment

I had this same issue years ago and fixed it on my 78 B210.  It's killing me that I cannot remember exactly what I did.

 

I think it had to do with the ceramic base plate under the Carb, the gasket between that and the intake and/or the down pipe missing on the primary that goes in the ceramic base plate.

  • Like 1
Link to comment

Today I replaced the distributor cap and rotor, and spark plug wires.  Thing runs better definitely.  Previous rotor was tan colored and made in US.  The new Bosch cap and rotor were made in Japan, FYI.  The hesitation upon acceleration still remains but the hesitation at steady speed seems improved.  I'm definitely taking my time, studying the manuals, learning how to use the tune-up test equipment, etc.  Next I'll complete the basic carb adjustments and see how this effects the initial acceleration.  Any advice on the carb tuning procedures will be much appreciated.  I took a picture of the carb tag, to compare to the previously posted pictures however it is blank (picture attached).  If I need to rebuild it, I'll probably do it over the winter taking my time.  That or I'll get another at national carburetor if people have had good results with them.     

IMG_5066.jpg

IMG_5089.jpg

Link to comment

Finally took mine down off the blocks in over a week. Got to drive it around today and got to say it runs amazingly good. Pulls away from a stop with idle and when you step gently on the gas there is no nose dive and stutter. Just smoothness. While it was apart I removed the carb and put the 99 jet in to replace the 108. Maybe a little less mid range and this makes the secondary cut in more pronounced. A 99 will be better for mileage to Canby.

  • Like 1
Link to comment

Finally took mine down off the blocks in over a week. Got to drive it around today and got to say it runs amazingly good. Pulls away from a stop with idle and when you step gently on the gas there is no nose dive and stutter. Just smoothness. While it was apart I removed the carb and put the 99 jet in to replace the 108. Maybe a little less mid range and this makes the secondary cut in more pronounced. A 99 will be better for mileage to Canby.

Can you elaborate on the 99, 108 jets?  Not certain I follow.

Link to comment

The carb has a fixed, (but removable) screw in orifice, to let fuel into the primary barrel. I have a car L20B engine and the carb comes with a 99 jet. This is the hole size, but what the 99 is I don't know... 0.99mm? Lower numbers are smaller, higher numbers are larger holes. The 99 jet is considered about right for the engine size and the vehicle to give acceptable gas mileage and power. I had trouble with my carb and put a truck L20B carb on and the jet size for it was 108. Now a truck is expected to be hauling heavy loads and working hard so a richer mixture over all is good for performance but not good for mileage, but mileage isn't really a big consideration with a truck that works hard. Another reason for different jet sizes is altitude.  If you were in Denver the altitude at over 5,000 feet causes the air to be thinner and this would cause the engine to run too rich so you would want a smaller jet to lean it out. Sea level has denser air so a larger jet is appropriate.

 

The second barrel flows more air than the primary and usually run jets around 150-160.

 

 

As I use my 710 mostly for my yearly trip to Canby and some extra traveling I need mileage more than performance.

  • Like 1
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.