Ok folks, pictured is the auxiliary carb on my 420g. I feel there is something missing as it spews fuel when engine is running and even more profusely when ignition is on and fuel pump is running without engine. Any advice on what to do? Can i bypass this device or make it function properly? Im not sure whether the fuel is coming from the piston/ plunger or one or all of the 3 bores? Cheers. Jj.

 

Clean and put in new seals. Probably ate up by old fuel and ethanol. Readjust to specs.

 

Ok but i cant see much to clean to be honest, the two screws release the copper needle. What seal exactly might be the issue? From looking at the exploded diagrams on the su carb site i am missing the dust shield kit on the thermo, but i cant see what difference it would make? Certainly not leak wise or am i very wrong?

 

There is a similar set up on the mk2.Basicaly it allows neat fuel into the manifold when starting from cold. The shield is just a pce of ally sheet and can easily be fabricated.(Pliers,snips,file and drill) The needle is used to adjust the fuel flow. The actual 'Valve' is under the solenoid. When cold the electro magnet operates and allows fuel to flow into the manifold. I would refer to the manual and check all the parts are correct. But you should hear it operate, when standing along side. When the engine is warmer it should stop the flow of petrol and the revs drop back.You should be able to see the detail in your exploded view. You can dismount the solenoid and make a manual test for the operation of the solenoid itself.
barry

 

Yes i have checked the solenoid and its working, as is the otter switch on top of the head which controls it. Only thing is, the copper plunger which i presume shuts off the fuel flow doesn't seem to be stopping the fuel, i presume its seal is perished.