I have a non-CC qjet on a 305 (LG4).

I've checked for vacuum leaks, changed any of the affected lines (I blocked all the lines off to start, then started changing any lines that leaked as I reconnected them.

I had the carb rebuilt recently by a mechanic - fixed a lot of little issues like my choke, but since the rebuild it went from 10KM/L to 7KM/L.

What should I look for next? I assume it has to do with the carb, since it's only happened since the carb was rebuilt....

The exhaust fumes smell of pure gas - I could choke on them they are that bad smelling of gas (In case that helps)....

 

Sounds more like an internal carb issue to me. just for kicks, are the idle mixture screws still capped or are they adjustable? Secondaries still closed?

 

Hm.. you positive it's not computer controlled? If it is/was, it sounds as though your O2 sensor was shot. Same thing happened to me. The fumes smelled like pure gas, and if you smelled them long enough, it would literaly bring you to tears.

 

Your mechanic might have used the wrong gasket or set the float level wrong. Might also be trash in the inlet seats.

There is also an issue with well plugs on these carbs. These are used to plug drilled holes at the bottom of the float bowl. Over time they loosen and leak. Fix is epoxy or JB weld over the plugs to reseal them.

To check for internal leaks, screw the idle mixture screws all the way in with the engine idling. If it dies, no leaks. If it keeps running, it's leaking.

 

Yup - it's definetely not CC.

And yeah - my fumes are just like that - bad enough that I'm sure the homeless people sniff my tailpipes for their next fix.

 

If I put the screws all the way in, should it die completely or run with a bit of a stumble?

It sounds like when I screw them all the way in that it should choke off (if there are no leaks internally) all the fuel at idle, so it has no choice but to die. Is that correct?

And what should I ask for at the store when I go to get the special tool to turn the screws (They look "D" shaped I think?)?

 

KD Tools has a neat flexible shaft carb adjuster that comes with various bits. The D driver is one of them. The bits store in the handle, the tool isn't that expensive. It makes getting around the waterneck and other plumbing much easier.