Old Ryobi Weed Eater Hard To Start

I have an old Ryobi weed eater 725r, 31cc with a walbro carburetor. Has not
been used in a couple of years, was given to me. I have cleaned and rebuilt the carburetor, changed the spark plug, checked fuel lines and primer bulb(all good),no scoring on cylinder or piston.
Can not get it to start on its on. If I use starter fluid it will start but quickly
shut off, however if I put a little gas in the carburetor it will fire up and run,quite good at that. Then you can pull start it with one or two pulls, the problem is if you let it set for 30 minutes or longer it will not start and you have to put more gas in the carburetor and start the whole process all over again. Any help on this will be
much appreciated.
Also on the adjustment screws for the carburetor, it has a plastic locking device on it , removed it , then there are two more pieces on the screws that only allow you to turn them so far,can not remove these pieces with out fear of breaking
something, any help with this also will be much appreciated.
By the way, I am a retired maintenance mechanic, so I have a pretty good mechanical background.

Thanks,
Analogman

 

Sort of sounds like the choke isn't working well. Is the choke closing off the opening of the carb?

 

When you say rebuilt the carb...exactly what is a rebuild?
You can likely buy a new carb for 25 bux and solve your problem.

 

Yes, the choke is working properly. All it is, is a plate with a sliding control arm.I am thinking it has to be a fuel problem.

 

The kit was only $7.00 dollars. Replaced screens,needle,gaskets and diaphragms,pretty much everything.So $7.00 and some time it is good as new,runs great once you get it started, its the getting
started part that is causing problems. I have to put gas in the carb. for it to start and stay running,if I use starter fluid it will start but will not stay running.

 

While you have it running spray/dribble some carb/brake parts cleaner behind the carb and along the mating surfaces if the engine tempo changes you have an air leak and can take the appropriate action. Have a good one. Geo

 

I agree with geo as well could be a vacuum leak that heals when warm.

Also, I thought that unit had both choke and primer?

 

Primer is off to the side by its self but I did replace it. I will try checking for a vacuum leak and see if that is the problem,will let you know. analogman

 

When you say you put gas in the carb are you talking about feeding some down the carb throat or working the primer.

 

I had exactly this problem on the weekend.
Mixed up some new gas and after a few pulls, fired right up and kept on running.
In retrospect, the can was sitting with gas for over a year....guess it was too old.