- Mon Apr 29, 2019 7:58 am
#82674
Jamesy, Thankyou but please see my original post - all that had been considered and dealt with before I posted.
What I found last night: I stripped the carb and confirmed the float height was correct and that the spring in the float needle was working.
However, I also removed the float needle jet to inspect it (it was perfectly clear) but I did find something else! The external fuel inlet tube on these carbs sits offset from the central float needle assembly. To connect the inlet to the float chamber, the carb body is drilled at an angle from the outside to make a narrow port which breaks into the threaded aperture in the centre of the float chamber, where the float jet screws in. After the port is drilled, the outside is sealed with a plain brass plug. Looking from the inside, I noticed that the bottom of this hole didn't seem clear; there was a small "tag" of metal from where this drilling breaks into the threads of the needle jet aperture - poor manufacturing quality control. I tried to see how the brass plug could be removed hoping to re-drill the port to clean it up; I couldn't see how that could be done. Instead I used a 2.5mm drill bit from the inside of the float jet aperture, in my hand drill, to clear away the tag of metal and drilled a little further up into the port.
After I'd finished, everything was blown through with an airline.
I'm keeping my fingers crossed that I've finally found the fuel flow restriction to the carb.
Built like a gun... could go BANG!