Yellow "Varnish"

Hi Sean

Sounds like everything should work.  Airflow under a cowl can do many funny things.  it may be something as simple as how the air comes over the carb body.  Perhaps do a test to check if possible.  Also consider if the fuel pump vent might be putting a drop into the airflow somewhere.  

I might do a dye penetrant check on the float bowl itself.  Aluminium is not a homogenous metal and it is possible that you might have a porosity somewhere.  The body, with the dark grey color, is a Loctite bath that should stop any tiny bleeds of fuel or air. 

Cheers

Sean, just went back and looked again at your pictures.  Consider replacement of the paper gasket under the choke body.  The 4 screws should have a drop of 243 Loctite on them.  If for some reason the gasket weeps it may be the problem.  Also the Loctite is for security on the screws however if one of the screws was not seated correctly the taper of the screw head might not seal perfectly. Just a shot in the dark here, might be worth a try.  

Cheers

RW, 

Have ordered a new gasket & O ring for the choke housing.

".........if one of the screws was not seated correctly the taper of the screw head might not seal perfectly."

Will the Loctite 243 act as a sealant on the screws? OR should I also use some gasket goo?

Hi Sean,

You don't need a sealant. The gasket is a dry install and the screws will be fine. The Loctite is more for preventing screw loosening. I apply a tad of white lithium grease to the "O" ring to keep it lubed, help it slide in place without abrading it and help preserve it just a bit. Make sure the screws are snuggly in tightened down. I've never had an issue with the choke gasket before.

Hi Sean

Yes Roger is correct, lube the O-ring with a bit of Lithium grease.  The gasket needs no sealant and the screws need Loctite to hold them from vibrations.  The taper head has to seal into the taper of the cast choke housing.  As long as the Loctite is on the threads of the screws they seal the threads from wicking any fuel up the thread into the taper seat area.  Don,t discount this may be coming from somewhere else under the cowl, like a tiny fuel drop from the pump vent port or elsewhere. 

I agree, don't use a gasket goo, it is unnecessary. 

Cheers