[Roadsters] SU air filter to carb gaskets /very rough idle

[Paul Bauman]

I ran into this issue years ago restoring my roadster. I eventually 
ended up changing my carb needle profile so the car would idle AND rev 
above 3000 RPM. The needles were designed for British SUs, but they work 
in the Hitachis just fine.

For those wanting to give them a try, I can only vouch for functionality 
on the  1600 and in California. The needle profile I use is the ADQ. The 
car will run regular without a burp.

Paul Bauman
Westminster, CA
67 1600




On 06/29/2017 09:26 AM, D Riedel via Datsun-roadsters wrote:
> Thanks for the advice guys.  There's lots of good stuff there to try.
>
> The fuel is either Co-op premium (a local operator), or Shell 
> premium.  For the latter, I'm not sure where the fuel is actually 
> sourced, but it is 91 octane and contains 0% ethanol.  The Shell 
> apparently contains a lot of cleaners (which they are very excited to 
> tell you about),and it too is 91 octane, with no ethanol.  However, 
> the fuel has sat in the car since late October.  I've had trouble 
> post-winter start-up with gunk-filled fuel filters in the past, but 
> not with this rough running issue.
>
> There is oil in the dashpots, although it may be a bit low (I know 
> it's covering the piston, but possibly only just)
>
> I will double-check the dashpot oil level, plug wires and spark along 
> with doing carb cleaner vacuum leak tests.
>
> I'll also give it a chance to run and little and check for uneven 
> carbs, stuck floats, etc.
>
> Meanwhile, Ross at Sports Imports is tracking down the gaskets for me.
>
> Cheers,
> Dave
>
>
>
>
>
>
>
>
>
> On Thu, Jun 29, 2017 at 3:46 AM, RWM <rwm at rwmann.com 
> <mailto:rwm at rwmann.com>> wrote:
>
>     John and Dave,
>
>     I use 'Stabil' fuel conditioner when over-wintering the car and
>     have never had a fuel-related issue.
>
>     Did have a sticking carb one spring, but that turned out to be a
>     sunk float. R&R and good to go again.
>
>     - Bob Mann, '68 2000 Solex
>
>
>
>     On 6/29/2017 5:08 AM, J Sandhoff via Datsun-roadsters wrote:
>
>         I second Paul's observation. Does Canada use oxygenates in the
>         fuel
>         like the States (i.e. ethanol; refined corn down here). If so I
>         suspect your gas has gone sour.
>
>         I rebuilt my SU's last fall, then the car overwintered. I'm
>         getting to
>         rebuild them again now 'cause they're totally gummed up with a
>         putrid
>         green sticky mess. California gas is the worst.....
>
>         -- John
>              John F Sandhoff jsandhoff at gmail.com
>         <mailto:jsandhoff at gmail.com>  Sacramento, CA
>
>
>         On Wed, Jun 28, 2017 at 2:40 PM, D Riedel via Datsun-roadsters
>         <datsun-roadsters at autox.team.net
>         <mailto:datsun-roadsters at autox.team.net>> wrote:
>
>             I started my 2000 SU the other day after it's winter break
>             and it ran so
>             rough I thought it might bounce off the mounts.  As I
>             peered around the carb
>             area hoping to spot something odd (maybe a leaky hose
>             causing a vacuum
>             leak?), I noticed that I don't have gaskets between the
>             air filter housing
>             and the carbs.  Yikes.  First of all, I really wonder how
>             this has been
>             affecting things all along, but second I'm wondering how I
>             might start
>             correcting the rough idle.  Since the car has never had
>             these gaskets since
>             I've owned it, whatever is currently happening isn't
>             exactly related (that
>             is, it ran fairly smoothly last year).
>
>             Any thoughts on 1) the missing gaskets, and 2) a process
>             of elimination to
>             smooth out the idle.
>
>             Thanks everyone,
>
>             --
>             Dave Riedel
>             '69 2000
>             Victoria, BC
>
>
>
>
>
> -- 
> Dave Riedel
> '69 2000
> Victoria, BC
>

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