Boy do I feel like a dolt. When I thought I was adjusting the fuel richness
mixture I wasn't doing anything. Now that I've actually found the correct
nut to turn it's actually changing the mixture amounts. I've got a start on
the tuning of these things, but I've got at least one bent needle and maybe
both are. The carb pistons are catching if the jets are adjusted in certain
places. I think I'll just order 2 new needles since they aren't too much.
I've got the performance about the same as before but now I've messed up the
low end power :( Oh well, I'll get it eventually.
Yesterday was my son's 4th birthday, so we took a ride in my 'motorcar' and
got icecream. We had a lot of fun!
-Mitch
-----Original Message-----
From: Mitch Planck [mailto:mitch@ias.net]
Sent: Tuesday, July 11, 2000 9:41 AM
To: 'datsun-roadsters@autox.team.net'
Subject: RE: lack of power
I've gotten several helpful responses with a few good things to check out. I
was working on this last night and I think I've found at least part of the
problem.
I started playing with the carb synchronization again and noticed that when
I turned the idle screw on the front carb the idle changed, doing the same
on the back carb did nothing. Turns out I had the screw so loose on the back
carb that the little turns I was doing didn't do anything - it was running
at it's lowest setting.
I tried syncing them up for a bit, but I didn't get far so I got out the
book (I've got a shop manual) and started following the detailed
instructions for syncing them up. It was getting dark and I needed to get
the kids to bed, so I didn't get to finish though. I was still working on
setting the throttle linkages to the proper length.
I also noticed that there was tension on the throttle and the choke when
both were supposed to be at a 'resting' state. I'm sure this was causing
part of the problem.
The way I was starting to figure this out was by using the little mirror
that comes with the colortune kit to look at the piston lift on the carbs.
I'm guessing that the lift should be the same on them if they are synced,
but mine were not - one had a lot more needle showing than the other. It
also looks like the stop nuts for the richness adjustment nut (the one on
the jet) are not set the same. One is farther from the carb body than the
other. Since I can also move the richness adjustment nut a different number
of turns on the front vs. the back, this makes it even harder to
synchronize.
At idle it was not running smoothly, but under throttle it sounds good and
revs quickly. No valve clatter, sputtering, or hesitation. I've had the
front carb apart and it looked clean and while I had it apart I cleaned it
up inside and out. I might need to do this with the rear carb. I'll also get
a bottle of carb cleaner - sounds like a good idea. It has a new fuel
filter, new oil & filter, new distributor, spark plugs and cables are about
2 years old but with almost no miles, and new 92 octane gas. I'll look into
a valve adjustment and check for vacuum leaks too.
Thanks very much,
-Mitch
'69 1600
http://beladi.stormloader.com
-----Original Message-----
From: owner-datsun-roadsters@autox.team.net
[mailto:owner-datsun-roadsters@autox.team.net]On Behalf Of
Fred_Katz@ci.sf.ca.us
Sent: Monday, July 10, 2000 7:47 PM
To: datsun-roadsters@autox.team.net; Mitch Planck
Subject: Re: lack of power
Hi Mitch,
My guess is that the carbs are fouled due to the old gas. You should take
them apart, and clean up the lines and fittings with carb cleaner and blow
them out with compressed air. It wouldn't hurt and your performance will
improve.
Because you have to raise the piston manually to get a smooth rev, I
suspect that not enough gas flow is happening to raise it when you open the
throttle. Do you get good results when you use the choke?
You would be surprised how old gas can get gummy and mess up the lines in
the
carbs, sort of like cholesterol does it to human arteries.
Fred - So.SF
BADROC
-----Original Message-----
From: CalSpeed@aol.com [mailto:CalSpeed@aol.com]
Sent: Monday, July 10, 2000 4:24 PM
To: mitch@ias.net; datsun-roadsters@autox.team.net
Subject: Re: lack of power
Was it sputtering? Hesitating? Running smoothly but with no power? It
could be a number of different things. Especially if you havnt run it in
over two years. My guesses would be that the carbs may be slightly
varnished
over with old gas. How is the fuel filter? Plugs, points, rotor...etc?
Do a complete tune-up and them your performance should change.
Michael "Calspeed" Carion
BADROC
-----Original Message-----
From: andycost@att.net [mailto:andycost@att.net]
Sent: Monday, July 10, 2000 1:27 PM
To: Mitch Planck
Subject: Re: lack of power
Sounds like the carbs are dirty or clogged. The idle
circuit may be plugged with varnish. Try spraying some
chemtool down their throats and pouring some in the tank.
NT
-----Original Message-----
From: SPL311RDST@aol.com [mailto:SPL311RDST@aol.com]
Sent: Monday, July 10, 2000 1:06 PM
To: mitch@ias.net
Subject: Re: lack of power
Also, a valve adj. is still a good idea, even if there is no clatter. ( This
is more than likely not your current problem) If they are adj too tight they
may not clatter, but can burn your valves. .017" HOT for both int & exhaust
is correct. (will try to dig up a FAQ sheet on basic valve adjustment for
you
- it's really not all that difficult)
Q: Is it idling down OK? Another thing that may cause rich/fast/rough/just
plain wrong idle is vacuum leaks. Typically the throttle shaft bushings get
worn and can suck air. Quickie check for leaks is to spray down linkagage
and
intake @ carb mount/intake at head (anywhere there's a gasket) with carb
cleaner while running - if there are any obvious idle changes, you've got a
leak.
Laurie :-)
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