Hello All:

1967 Volvo 122S wagon. My lovely pair of HS6 carburetors are getting a tune, and I decided to check the dashpots for oil. I found them to be rather dry. I read the SWEM article "What's Wrong with SU Carburetors?" and there was a suggestion of filling each dashpot with oil and then holding a rag over the top while moving the piston up to catch the overflow that squirts out. What I am finding is that something squirts out every time I lift the piston, until I pretty much force out all of the oil I had in there in the first place. Should I only lift the piston once? I have tried moving the piston quite slowly and I still get a squirt.

Cheers,

Jeff Pucillo

Another way: I use a disposable plastic hipodermic (whitout needle). I put 4.5 cc on my Stromberg ZS175. It is the volume needed to fill the dashpot without overfill it.

The first time I retire the air filter, and move the cylinder up with a finger, after it, I fill oil from the hypodermic on small bits, putting the piston on and cheking overfilling each time. I overfill at 4.7 cc, then I know i will be use the previous dose: 4.5 cc.

You can made a similar measure for your carb(s).

On following refills, I take all old oil out with a syringe (with a bit a plastic tube as a extension - plastic tube taked from a venoclisis kit - easy on any pharmacy - or from a "pajilla" - popular adminicule for drink coca cola, sorry I dont rename the name on english), and refill it with fresh 4.5 cc dose (I use ATF and the quarte bottle has a lot of doses, no problem on spare some cc of oil).

Happy volving
--
Joaquin (yogui the bear) / Rojo 121 / Lima, Peru

Jeff, you're not pumping out all the oil that way. It really only needs that little, and you won't need to check it again for a year. If you have more than that, the carbs will eventually pump it out themselves, leading to the myth that SUs somehow "use" oil.

(I think that was my article, with all deference to Ron and SWEM.)

You say, "...........the myth that SUs somehow "use" oil."

If they don't "use" oil, why do they need to be refilled?
It certainly goes SOMEWHERE!!
--
George Downs Bartlesville, Heart of the USA!

If you need to add oil (or think you need to add oil) more than once a year or so, I bet you're overfilling.

Maybe 2 or 3 times / year but even so, if you EVER need to add oil, it is
going somewhere. Where??
--
George Downs Bartlesville, Heart of the USA!

I dunno. I can't remember ever running out.

Hello Phil:

As I was typing I was thinking "was that an SWEM article?" If I incorrectly cited my source, by all means I apologize. Thanks for the response.

So, to review: I do indeed pump the piston several times at slow speed. Oil will still pump out at that point, but no worries, right?

Cheers,

Jeff Pucillo

Jeff, I usually just lift each piston all the way once, but I don't think there is any harm in doing it a few times. If there is not enough oil, you'll have a stumble opening the throttle, so that's your indication that something is wrong.

Guys;

I certainly use and recommend the "lift the dashpot" technique because it: 1. Checks for free DP movement including metering needle/jet contact
(maybe the most important aspect of an SU carb!)...good to do periodically!
2. Pumps excessive oil into the rag instead of bloodying the underside of hood (and I lift a couple times...after the second time, it's pretty much done squirting out...unless you really overfilled it)!

As far as the dampening oil going away...if you pour it in, and after some time it is less or gone...I call that "using" it! I believe this is caused by the vacuum above the dashpot (which lifts it) also liberating miniscule amounts at a dead-slow rate, but nonetheless relentlessly leading to its consumption.

Cheers from S Dakota...God's country!