I am in the process of trying to get a 31cc engine on an old cultivator
running. It uses a Walbro carb. I haven't been able to get it running
properly. I have taken the carb apart, soaked it in cleaner, blown out all
the channels with compressed air, and replaced the parts that come with the
rebuild kit. I can get it to run, but I'm not having any luck adjusting the
low and high speed idles to get this to run without stalling out. I checked
the muffler to make sure it's clear and there are no screens that I can see,
just a straight path to the outside. I have noticed that every time I leave
it for awhile, when I come back there is gas in the cylinder and I must take
out the spark plug and drain it and dry the spark plug before I begin again.
I took off the gas tank and checked the two fuel lines and they look fine.
Is this normal? What would make the fuel leak into the cylinder when not in
use? I replaced everything inside, at least I think so. The rebuild kit was
universal, so there were a few parts left over. There were two aluminum
discs and a screen I didn't use because the ones in the carb were in there
in such a way as I couldn't figure out how to get them out. Otherwise,
everything that matched up with the kit was changed out.
Start with the low and high needles at 1-1/4 turns. Get it running and
keep it going for about a minute. Then start with the low speed
adjustment. Turn it in very slowly and find the point at which it runs
at the highest idle. At this point it should die out when trying to
accelerate. Turn the low speed needle out slowly until you can hit the
throttle and it accelerates without hesitation. Now you can move on the
high speed adjustment. Run it at full throttle and slowly turn the high
speed needle in/out to find the point at which it is running at the
highest rpms. At this point it will sound good and run well but not have
much power under a load. With it running at full throttle back the high
speed needle out slowly until the engine just starts to falter and miss.
That's where you want to leave it. It should now accelerate quickly and
when put under a load it should sound smooth
How can you tell there is gas in the cylinder? Is it full?
No that is not normal. There is an inlet valve in the carb that is
leaking, it's either not adjusted correctly or there is trash keeping it
Thank you for your input.
The carb sits in a circular plastic housing that has a plate the
attaches over it that also has the choke, medium, run knob. I have this
plate off while I'm trying to work on the carb. If this thing sits
overnight, there will be several tablespoons of fuel trapped in this
plastic housing. It has to be leaking out the carb. Some of the gas is
leaking into the cylinder also, because if I take out the plug before
even trying to start it, the plug is wet and about a teaspoon of has
drips out the spark plug hole. I'd like to know more about a stuck
valve and how I can clear it.
If you bought a generic carb kit, it will fit other carbs as well. If
they sent you a new metering lever( the lever with the spring under it,
It would need to be adjusted). If I am right, try this remove the
metering lever, spring and needle, spray carb cleaner in the needle
hole and swab out good, pressing down firmly and twisting the Qtip. Now
if you have the old lever, reinstall it. BE SURE THAT THE GASKET GOES
TO THE FUEL RESERVOIR FIRST AND THEN THE DIAPHRAM AND THEN THE COVER.
iF YOU HAVE THEM IN REVERSE, the diaphram pin that trips the lever, is
now laying against it an holding it open and fuel is being pumped into
the carb.When you sit it aside fuel in the reservoir continues to drain
into the venturi. If you do not have the old lever, look and see if you
have the spring standing straight up and in its seats.Now take a small
screw driver and hold down on the needle side of the lever and bend the
flat side up or down until the lever is level with the sides of the
channel it sits in.
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