I had an idiot use oven cleaner to clean the condensing unit
on a make line at a pizza place. Later the unit failed and
when I opened the control box, the cleaner had gotten inside
on the wiring, damaging it and allowing all the magic smoke
Back in the '50s we used to rebuild the old Plymouth's carb every year.
Took it to a local mechanic and he would charge a small sum to soak it
overnight in his dip tank. However, all of the instructions I've read
recently on rebuilding small carbs...lawn mower, outboard motor, snow
blower, etc....caution against using that type of cleaner as they claim it
will dissolve some small parts in the carb that are best left alone. A
spray cleaner, only is recommended.
I wouldn't dip a whole carburetor but the main casting is just
aluminum and brass. These little weed eater and chain saw carbs are
real easy to take apart but the main jet is virtually impossible to
get to for cleaning.
They are really only about $50 on the net and that will certainly fix
the problem but it seems like a waste.
On Mon, 26 Oct 2009 16:11:59 -0400, "Stormin Mormon"
I had 2 with exactly the same symptom (start, won't run) and both
would not flow fuel from the chamber with the diaphragm and inlet
needle through the metering jet. I got one open and things were fine.
The other is still hopelessly plugged. I bought a carb and fixed that
one. I would still like to fix the original for a spare.
I did figure out how all that fuel flow works on those little 2
strokes so it was a good learning experience. It is not really much
like the car carbs or boat carbs I have done all my life.
The primer bulb actually sucks fuel thorough the system and pumps it
back into the tank. The stuff under the "big screw" end is the fuel
pump and the "4 screw" end is the reservoir for the main metering jet.
The jet is definitely plugged. Having 2 carbs that are basically the
same is a handy trouble shooting tool. You can compare what happens
when you shoot carb spray in each hole.
BTW in my foray through the net I heard several times not to blow out
these things until you take it apart, particularly the "big screw"
side since that is where the fuel pump is and you will blow the little
check valves (just flaps of mylar)
The way I finally cleared the jet I could blow open (another carb) was
to plug one end of the venturi with a test tube size rubber stopper,
fill it with lacquer thinner and blow air in the other side. Do this
outside and use a face shield. I had the whole thing wrapped in a shop
towel and it still blew thinner everywhere. (150PSI air).
It did blow the jet open tho. The other one, no joy. Plugged solid.
I am going to try soaking in carb cleaner now that I have my machine
going with a new carb and when I think I have the old one fixed I am
going to swap it back. Then I know I have a good hot spare. Yes I will
be sure I blow all the gas out ;-)
On Mon, 26 Oct 2009 19:41:10 -0400, gfretwell wrote:
Heh, yeah. I've got a couple of 'em here (little Walbro things) that were
DoA but _seem_ to have clear pathways. Problem is they'd both been screwed
around with before I inherited them, so the mixture settings were a mess,
but there's also no guarantee that someone didn't screw with the needle
I got one to the stage where it'll run, but has a habit of dying after
5-10 minutes - but I can immediately start it up and get another few
minutes out of it. Something's obviously not doing its thing right, but I
don't know if it's pump or needle (I don't think it's mixture, not when it
runs that long before flaking out)
The other one's still sick - it'll do that thing where it'll start and
hold idle, but die as soon as the throttle's opened, no matter what the
mixture setting, so I wonder if that one's got a partial blockage
One day I'll motivate myself to treat one of them to a new
needle and diaphragm set and see where I get... it's too cold here now to
be playing with them until April or so, though :-)
Yeah, that makes sense if yours are anything like mine - it'd probably do
more harm than good. Thankfully they come apart (mostly) pretty easily :-)
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