Jerry, True, the piston does raise faster and takes the needle with it, - BUT,
in doing so, it reduces the velocity of the air, reducing the amount of fuel
picked up by the air stream, thinning the mix. As Keith described, the slower
piston acts like an accelerator pump, When you first depress the pedal, the
throttle butterflys open, but the piston slowly raises. so, at first, the air
velocity is siphoning more fuel from the nozzle, giving that "spurt" of fuel
-----Original Message-----
From: Jerry Krakauer <jsk977@optonline.net>
Sent: Mar 30, 2004 1:25 PM
To: Keith0alan@aol.com, sandhoff@csus.edu, datsun-roadsters@autox.team.net
Subject: Re: Dashpot oil (was: quick question)
Keith,
Since I've been running Solexs for 37 years, my SU experience comes from
working with MGs and Triumphs in the 60s, but if remember correctly, thinner
oil will give you a richer mixture more quickly, not the other way around.
The thinner the oil the quicker the piston moves up which takes the needle
with it, thus moving the lower thinner part of the needle to the fuel
dispersal area of the jet providing a larger orifice area. The choke works
on the same principle by pulling the jet down to a thinner cross section
area of the needle with the piston still down all the way at idle. The
acceleration stumble is caused by an overly rich mixture, not lean.
Jerry Krakauer
----- Original Message -----
From: <Keith0alan@aol.com>
To: <sandhoff@csus.edu>; <datsun-roadsters@autox.team.net>
Sent: Tuesday, March 30, 2004 9:22 AM
Subject: Re: Dashpot oil (was: quick question)
> The thicker the oil the more "accelerator pump" behavior. Slowing down the
> piston causes the mixture to richen on opening the throttle. The thinnest
oil
> that does not stumble on acceleration is best. As to me, I use 10-40, same
as
> the engine. If you want to experiment try motorcycle fork oil. Should be
able to
> get it in lots of different weights.
>
> keith
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