bikz

guys, in a Webra 55 engine 2 stroke which has been sitting idle for about 10 years now, i started it today, this is what going on with the carb:

a) the fuel is spitting out from the carb...visually its spitting/ sputtering out of the carb as though there is way too much fuel going in and i suspect that is the issue here...

b) the high speed needle seems to be doing nothing ...upon fully closing the needle also, the engine starts...i'm assuming the needle is completely not functioning ...idles very very strongly but upon opening the throttle, the engine dies....

my first question - when the high speed needle is fully closed, can any fuel still pass through the venturi? can an engine start with the needle fully closed? edit

second question- what could be the problem? is the needle faulty? if so how and why? i completely screwed out the needle and visually it seems fine.

bikz

having done a little research since my first post, im pretty sure that if the needle is fully closed, no fuel can pass through the carb...which means there is an issue with my needle....

any idea why it is not closing the venturi when the needle is being turned close? even at full "close" it is allowing fuel to pass through...all help is highly appreciated..
thank you

1QwkSport2.5r

If the needle was over tightened, it may have wallowed the seat out some. Try to tighten the needle a little tighter and see if fuel stops.

I don't think this problem would cause fuel to spit from the carb when running unless the needle setting is way too rich or the engine is running backwards.

bhorton

My Feedback: (26)

If the needle is closed all the way no fuel should be passing through it. Because the engine had not been used in 10 years my guess would be that dried fuel/oil is preventing the needle from closing. Try taking the needle out & running a very small wire into the hole several times. A tie wire from a package of bread with the plastic stripped off of the wire will work. Soaking the carb in glow fuel will soften any dried fuel in the carb.

bikz

thank you guys...also, i had forgot to mention that the engine was fully "jammed"/mucked up, especially the carb prior to geting it back started over the weekend....what i did was boil it in water and that released up everything to an extent.....any idea if this could have messed up the carb?


i think its spitting fuel because the needle is completely not functioning.....therefore the fuel is going in to the carb at "full open" even when it has been literally been fully shut

-edit- please refer to the posting below....the needle is not at "full open" when fully shut but/however is letting in some air/fuel in at fully turned shut.

bikz

guys i did try an experiment...(all passageways are clear and clean by the way)
...took out the throttle barrel and shot light through the opening....in a dark room i viewed the fuel inlet and could see light through the fuel inlet without the needle...
upon screwing the needle, the light did get dimmer and at the point of full close of the needle, there was a micron of light still visible....almost no light through except for a slither of it....is this normal? however i doubt at this point, when fuel is passing through and not light!, that little amount of fuel is not sufficient to start the engine....am i right?
therefore how did the engine idle so well yesterday with screw completely turned shut?

the pope

Had the same issue with a T.T. 54 4stroke . Replaced needle seat etc , came as a set but I wasnt sure so ended up with double of some parts . Hook up a piece of fuel tube and with the needle closed if u can blow air through replace these parts if u can find them and away u go . Cheers

bikz

which is the needle seat sir? i went on the webra website, they don't sell parts for the carbs.....only entire carbs for sale.....

is the needle seat the part which is connected to the rest of the carb which has the fuel inlet nipple and high speed needle on it? if so can this part be removed from the carb?

the pope

Hey dont call me sir ! I get a wee bit nervous when that happens , it usually means Im in trouble . As u can imagine a needle is like a man part and the seat a girl part . Like a marriage made in heaven . Im not familiar with the engine u have but its probably similar to most engines . Just strip the carb down as far as you can but if the parts are no longer available buying a complete carb maybe your only option unless u have a spare carb from another brand that will fit . Also check that the needle hasnt moved back in its knurled holder ( thats the only way I can describe it at the moment ) so it doesnt completely close . If this is the cause of your problem u can gently tape it back or press it back into its correct position but not while its still attached to the engine or carb . Good luck

bikz

i wasn't too sure if i was actually dealing with the Pope or not.....i could have said your Highness or your Almighty (not exactly sure how to the Pope is referred to but that could have been an overkill ;-)

hahaha...anyways mate cheers and thank you for the brilliant advice.....haven't been flying for years now so my knowledge has become a little rusty...thank god for this brilliant forum....

Mr Cox

If the main needle leaks a little it is not the end of the world. I guess there is not enough fuel leaking through to sustain running at full throttle?

The low end needle will then take of the low end (and middle range), the high-end needle has to come out a little for full throttle running, and all is fine...

bikz

thank you for your advice.
However don't you think with a leaking high speed needle, there is too much fuel going through as opposed to not enough fuel ?

the pope

With mine it was just running too rich with the needle fully closed . No leaking fuel . I cant even fully remember the exact root cause , been too long . Cheers

Mr Cox

Try the advice with blowing through a fuel line while turning the high speed needle (with the carb at wide open throttle). When closed you shouldn't hear anything and when you open the needle you will hear a slight hissing sound, this will be about the right setting and is usually good enough to get an engine started.

If fuel syphons into the carb then the tank is simply positioned too high. Try running the engine in a test stand first so that you have easy access to everything.

On the older carbs it was possible for the needle to slide a little in its brass holder, thus not reaching it seat to fully seal of the fuel. If you webra has that kind of needle you can carefully press it back. This would be done with the needle out from the carb and preferably using a drill press.

bikz

thank you once again to everyone on this thread......my knowledge has gone from almost zero to hero on needles and needle seats from this thread... ;-) ..i hope i sort it out and will report the good news here accordingly......CHEERS