[Roadsters] High Speed Hesitation / Potential Fix?

[Keith0alan at aol.com]

Try heavier oil in the dashpot. If it cruises fine then the mixture is  
good. Stumbling on acceleration is a sign of not being enriched enough on  
acceleration. Thicker oil will enrichen more on acceleration. Try some 30 wt  
engine oil and see if it gets better.
 
 
In a message dated 5/2/2015 2:46:55 P.M. Pacific Daylight Time,  
datsun-roadsters at autox.team.net writes:

Potential worn throttle shafts.  Adding choke to enriched mixture  makes up 
for unmetered air that is coming from someplace.  


Check the play in throttle shafts and then look for other areas that  might 
do same. 


Also how's the float bowl fuel level?  Adding choke also drops  nozzle to 
level of lower fuel bowl. But if it runs well otherwise and always  idles 
decent then neither may apply. 


All just wags without being there. 

Dave Sommers  
Dive Hatteras
703-517-3724
703-818-1850


On May 2, 2015, at 16:55, wattaj via Datsun-roadsters 
<_datsun-roadsters at autox.team.net_ (mailto:datsun-roadsters at autox.team.net) >  wrote:




 
Update:  Reassembled and  plugged the lifter piston hole, and no 
improvement.


Things I have done:
    1.  Verified the timing and vacuum  advance are set and working 
correctly.
    2.  Adjusted the valves to correct  clearance.
    3.  Changed the dashpot oil to ATF.
    4.  Disassembled the Domes, Pistons,  Needles and cleaned.
    5.  Reset the needles to correct depth  according the Z-Therapy video 
method.
    6.  Checked to make sure SU pistons are  moving at the same pace within 
the domes.
    7.  Checked for a kinked fuel lines  from the float chambers to the 
nozzles.
    8.  Set/Tuned the carbs according the  write-up by Keith Williams.


The only thing that seems to  get the car running smoothly and able to 
accelerate once at speed is to pull  the choke out or set the mixture to very 
rich.


I would maybe suspect the  distributor is worn out, but if that were the 
case I wouldn't think pulling  the choke out would make any difference.


Thanks,
Alan







 
  
____________________________________
 From: wattaj via Datsun-roadsters  <_datsun-roadsters at autox.team.net_ 
(mailto:datsun-roadsters at autox.team.net) >
To: "_datsun-roadsters at autox.team.net_ 
(mailto:datsun-roadsters at autox.team.net) "  <_datsun-roadsters at autox.team.net_ 
(mailto:datsun-roadsters at autox.team.net) >  
Sent: Saturday, May 2,  2015 10:49 AM
Subject:  [Roadsters] High Speed Hesitation / Potential Fix?



 
 
I have been chasing this  issue for a while and I am hoping I may have 
found something but would like  your feedback.  (Thanks in advance!)


When cruising around 3000 to  3200 RPM, if I press on the accelerator, the 
motor wants to hesitate or  cough, it will eventually get beyond this, but 
is annoying.  I have  done my best to tune things and the only thing that 
helps is making the  front carb run very rich.


Today,  when dissembling the carbs, I noticed the front carb was missing 
the Lifter  Piston (part # 16324-10400) that  you can use to test the 
lean/rich mixture from the bottom of the carb  without having to put your finger 
into the throat of the carb.  


Could that be creating a  vacuum leak and cause of my issue?


Thanks,
Alan


67-1600 (with a 67.5  engine)
Portland, OR




 
 









________________________________________

_datsun-roadsters at autox.team.net_ (mailto:datsun-roadsters at autox.team.net) 

Donate: http://www.team.net/donate.html
Archive: http://www.team.net/archive
Forums: http://www.team.net/forums
Unsubscribe: 
http://autox.team.net/mailman/options/datsun-roadsters/wattaj@yahoo.com












________________________________________

_datsun-roadsters at autox.team.net_ (mailto:datsun-roadsters at autox.team.net) 

Donate:  http://www.team.net/donate.html
Archive:  http://www.team.net/archive
Forums:  http://www.team.net/forums
Unsubscribe:  
http://autox.team.net/mailman/options/datsun-roadsters/divehatteras@aol.com




=

________________________________________

datsun-roadsters at autox.team.net

Donate:  http://www.team.net/donate.html
Archive:  http://www.team.net/archive
Forums:  http://www.team.net/forums
Unsubscribe:  
http://autox.team.net/mailman/options/datsun-roadsters/keith0alan@aol.com



-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://autox.team.net/pipermail/datsun-roadsters/attachments/20150502/0691e2cc/attachment.html>