webra 35 starting problem

[kalm2kaos]

Hi all, new to this forum, so big HELLO to one and all.
Got a problem with the above engine, cant start the begger, well not very easily. once its running it goes fine above about 1/4 or 1/3 stick, plenty of smoke, plenty of go, doesn't bog down on a climb or miss a beat. changed all the lines, including clunk. New (and checked) os8, had both needles out and blown through the carb using a small compressor. Got it going today(eventually), ran the tank out, refuelled then went to start up and it didnt want to know. Hadnt changed any setting of needles. would run clean for a few seconds, then burble a bit and die at low throttle.needle settings are 2 turns on idle, and 3/4 on main. Bearing in mind the top end appears to be ok at this setting has anybody got any ideas? I'm pulling my hair out on this one. The oil is a lovely clear consistency, not black. Its running in a raptor 30, using a yeasu muffler and sport 5 fuel.Has an inline fuel filter and this is clean. All constuctive ideas would be gratefully recieved :lol:

[Raptorite]

Hi Kalmtokaos,

First of all, welcome to the site

Now, on to that webra problem, I have found through setting up many a webra motor recently that they have a tendancy to do just about what they want, when they want. That said, to get them running well they like to have both needles adjusted in equal and opposite amounts, i.e. if for example you lean out the top needle a click or two, you may also need to richen up the bottom needle a tiny bit.

From what you describe as the symptoms, it almost sounds like it is leaning out just before it dies, in which case I would suggest you richen up the bottom needle a bit.

The best way to test the bottom needle is to do the "pinch test".

If you are not sure what this is, with the motor ticking over at idle, pinch the fuel line with either a cut off clip or your fingers, what you should expect is for the motor to run normally for around 3 seconds, then rev up a little as it leans out and then stop.

If it starts reving up imediately, it is too lean, conversely if it runs normally for more than 3 seconds it is too rich. Test and make adjustments as required and see how you get on.

Cheers,

Pete.