[Mgs] Carb cleaning

[Richard Lindsay]

Paul had some good suggestions and I agree. But Tom, I find myself
pondering over your word 'clean'. Do you mean 'shine them up' or 'remove
deposits from inside'?  Carb cleaner is good for both jobs and let me add a
word or two if cleaning inside is the quest.

I just cleaned the SUs on my TD and doing so made a world of difference.
But first of all, someone here said, "Most carburetor problems are
electrical." That's a funny turn of phrase but it's true. I tuned and tuned
my TD's SUs before putting the timing light on the TD and discovered that
the timing was jumping around. New springs in the distributor's mechanical
advance calmed the jitter making carburetor tuning a one time affair. But
back to cleaning.

I marked the covers for rotation position, removed the damper pistons, and
removed the covers, setting them aside carefully, labeled 'F' and 'R'. I
then lifted out the air pistons complete with needles, dumped out the oil,
and set them aside with their covers.

Using fresh, clean, pipe cleaners wetted with carb cleaner, I carefully ran
the pipe cleaners up and down the jets, switching to a new pipe cleaner as
the previous one became discolored. I then wiped the chokes clean with a
shop rag and carb cleaner. That finished the carb bodies.

I next cleaned the air pistons and needles with carb cleaner and shop rags
paying particular care to protect the needles. I also sprayed carb cleaner
into the damper bore, washing out any old oil. The insides of the covers
were wiped clean and the piston bores were flushed clean.

I live in a very humid climate where rust flashes quickly. I don't know
whether the air pistons and bores are stainless but I took no chances. I
applied 3-in-1 oil to the air pistons and inserted them into the bores in
the covers, coating all with light oil.

Back at the car I verified that the heights of the jets and were the same
then switched on the fuel pump. Petrol came to the top of one jet but not
to the other. I adjusted the float bowl valve until both levels were the
same.

Back in went the air pistons, the covers on and the screws tightened
gradually checking for proper piston drop as they were snugged down. BTW, I
use lockwashers on the carb bowl screws so they don't work loose but more
importantly, so they don't need to be over-tightened.

The rest is tuning. Airflow was balanced and the mixture was reset.

The part I left out was cleaning the needles but that's quite controversial
so let's leave it at, "I cleaned the needles."

And of course, this is just my story, not an authoritative treatise on SU
maintenance. Maybe it helps someone.

Rick

On Sat, Apr 25, 2020, 5:54 AM Thomas Gunderson via Mgs <mgs at autox.team.net>
wrote:

> What is a good way to clean SU carbs without removing them?
>
> Tom Gunderson
> 1957 MGA 1500 rst
>
> Sent from my iPhone X
>
>
> _______________________________________________
>
> Mgs at autox.team.net
> Donate: http://www.team.net/donate.html
> Suggested annual donation  $12.75
>
> Archive: http://www.team.net/pipermail/mgs http://autox.team.net/archive
>
> Unsubscribe:
> http://autox.team.net/mailman/options/mgs/richardolindsay@gmail.com
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://autox.team.net/pipermail/mgs/attachments/20200425/9f635cb0/attachment.htm>