Awesome. Shall try. May take me awhile to get to it. I don't have compressed air available but can accomplish the rest. Also, after watching some videos, I'm suspecting that one possible reason the primer bulb can't pull gas up is that the diaphragm on the platform beneath it is bad or the screen beneath that diaphragm is clogged. Thoughts?
Thinmibg maybe I should just get a rebuild kit. I've not rebuilt a carb fully yet but these seem simple and straightforward enough.
Does not need to be a compressor, you can use a vacuum cleaner that has a blower outlet, electric paint sprayer or a leaf blower with a length of hose shoved in the nozzel .
All you need is air blowing through the carb to see if it can make fuel come out.
As for rebuilding them, it is neither simple nor strait forward, particularly if they are full of old dried fuel as the solvents that will dissolve the fuel will also attack the check valves.
Apparently Walbro now have one that is safe but at the price of a can it is cheaper to replace the carb.
What you see mostly on You tube are ego maniacs with a can of regular automotive carb cleaner and yes it works, right after you have done it.
So you can get all the thumbs up and accolades.
But what happens in reality is the damaged check valves start to swell up and the tool gets progressively worse & worse till it will no longer work.
However the "glory seeking Y tube heros " rarely bother to do an update saying all their work was a dismal failure & they had to fit a brand new carb.
I found this out the hard way by continually being required to do warranty repairs on tools that I had previously repaired ( I give 12 month warranty on repairs ).
So I went on a education campaign did a massive amount of research that changed the way I look at cube carbs totally.
So now I do exactly what I have advised you to do, start by checking the fuel tank, fuel lines & filter the see if the carb atomises fuel properly
The upshot was an ultrasonic cleaner that is just about worn out after 3 years, a lot of experiments with cleaning solutions and a good quality pressure / vacuum pump.
To my surprise I found most of the problems, other than a gummed up carb were pressure leaks in the tank. cap, vent or lines.
The only time I fit a new needle is if the old one is stuck in the carb.
It is just about impossible to determine if the fuel pump is working to it's specificed capacity so if the carb is going to be pulled apart then all diaphragms & gaskets get replaced.
There are only 2 kinds of cube carbs, rotary valve & butterfly & Walbro do have videos on how to strip & rebuild them , but remember they show a brand new unused carb being worked on, yours will be a bit different.
As a matter of course I always replace the manifold gasket as most impulse feeds go through this gasket and they do go hard & leak with age
