I have a 2-cycle trimmer that was working just fine. Then during it's last
use the speed began declining while in full throttle mode until it finally
died. I changed the spark plug and now it only runs with the choke closed.
If I try to open the choke or let off the throttle the engine dies. Any sug
On Fri, 3 Jul 2015 15:57:42 -0700 (PDT), email@example.com wrote:
Just guessing, dirt in a carburetor port.
Closing the choike limits the air and increases the ratio of gasolne to
air. If there is very little gas going into the gas-air mixture in the
first place, that could be making it rch enough to run.
Does it put out black smoke when it's running with the choke closed? If
it usually does and now it doesn't that supports my view.
What to do? What's that spray int he black and white can meant to
clean carburetors. I'd try that, all over, before rebuilding the carb.
Gum out. And maybe mix some gum-out that's designed to be mixed with
the gas with the gas,
If you decide to clean the carb better than this, post back.
On 7/3/15 6:57 PM, firstname.lastname@example.org wrote:
Mine is nearly 35 years old, but I guess they are the same in many ways.
I have a Walbro carb. On the side with the fuel inlet is a plate held
by a center screw. That's the pump compartment. With the choke on and
the throttle open, the pump gets bigger air pulses to pump harder. For
me, the problem has usually been that moisture in the fuel has caused
the outlet screen of the pump to clog. A q-tip and a little cleaning
solvent will fix it.
The last time, gas deposits on the face of the body against which the
pump gasket seated, showed that I had an air leak, which kept the pump
from working right. Removing the deposits fixed it.
Carburetor deposits and vacuum leaks are much more likely on today's
2 strokes since most run on a weak oil mixture, using low ash
clean-burning (relatively) oil - and ethanol gasoline. This adds up to
low exhaust deposits, and all kinds of sneaky stuff clogging up fuel
systems and deteriorating gaskets etc.
On Friday, July 3, 2015 at 9:42:18 PM UTC-5, email@example.com wrote:
last use the speed began declining while in full throttle mode until it fin
ally died. I changed the spark plug and now it only runs with the choke clo
sed. If I try to open the choke or let off the throttle the engine dies. An
Someone gave me a WeedEater leaf blower recently that had the problem that
Tony describes...nearly closed-off exhaust port.
On 7/4/15 12:24 PM, firstname.lastname@example.org wrote:
I believe port blockage is a gradual process that reduces noise and
power, but the motor still starts normally. I've cleaned carbon from
ports and sometimes mufflers, but I've never had enough to notice a loss
... or the gas/air mix. Mine can easily be set too rich, and it might
seem satisfactory. I set it as lean as it will still respond to the
The OP said his problem happened suddenly. Mine has usually happened
because the screen got gummed by a material caused by getting moisture
in the fuel. It's hard to see because it's colorless and translucent.
It hasn't happened so much since I started mixing fuel 500ml at a time
in a 600ml soda bottle, so it's sealed against air and used pretty
quickly. I discovered that epoxy cement could seal the hole where the
fuel line exits the tank. That helped, too.
The second cause in my experience has been air leaks around a carburetor
I found a third cause at my neighbor's this year. His fairly new trimmer
suddenly wouldn't run without the choke. He'd refilled it with fuel that
had been sitting in a milk jug a couple of years. When I finally
figured it out, I dumped the tank back into the bottle and filed it with
fresh fuel from my bottle. After it burned the fuel in the line and
carburetor, it ran like new.
Second this. Esp, if you run it part throttle. A factory service guy
told me these engines are designed for either idle or WOT. Ours gets
plugged every couple of years, . (I do run part throttle.)
Anyway, there's a 'spark suppressor' screen in the exhaust port. I
hit it with a propane torch. That ignites the wet stuff. After that
burns off, just brush the residue out, and good to go.
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