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My blower wouldn't pull at all. Piston seized? I removed the spark plug and pulled it on a geyser of raw gas shot out. I'm thinking of float and needle valve But I don't think it has one. What should I check? The blower is about 10 years old And it was running fine.

Yes it has but it is a little different
It is called a metering valve and is moved by the metering diaphragm.
Both Walbro & Zama have detailed instructions about how the various carbs work & Walbro actually have some videos

This gives me a place to start looking pretty thanks very much.

Also check the tank vent ( usually in the cap )
Generally they leak so don't hold pressure but they can block, cause the tank to over pressurise .
At around 15 psi the metering valve opens ( called pop off pressure ) and that causes the engine to flood
But usually it will be either crud holding the needle open or a tear in the diaphragm
But read the manual & watch the videos
You can ignore 90 % of what you see on You tube and 99.9999% on what you see on face book anout cube carbs as most of the posters are totally clueless

While removing the carb I got a significant "puff" when I removed the fuel line. I have a Walbro, WYA 81 735. Thanks for the prompt reply.

Hmobley50 said:

While removing the carb I got a significant "puff" when I removed the fuel line. I have a Walbro, WYA 81 735. Thanks for the prompt reply.

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A line trimer & chain saw fuel system is a closed loop pressurised system.
They have to be so that the tool will run upside down
Very similar to outboard motors on boats.
The fuel pump in reality is a pressure pump that pumps up the tank to around 5 psi to 10 psi
Some where in the system there is a pressure valve, usually in the cap to maintain that pressure to force fuel into the carb.
A pressurised system has a supply & return line.

Earlier they just had a single supply line which tried to suck fuel out of the tank into the carb but eventually they found it works better to push the fuel rather than pull the fuel

When you pressure test a hand held, the first thing you do is to pressure test the fuel tank in both pressure & vacuum
It should suck without obstruction but be able to be pumped up to around 7 psi.
This pressure should bleed off reasonably quickly in a few minutes.

If you still had pressure in the tank then the cap or vent ( where fitted ) is not working.
If the tank over pressurizes then it pops the metering needle off the seat ( Called pop off pressure ) and floods the engine with pressurised fuel .

Those with baby minds that are facinated by things that move wax lyrical about testing pop off pressure on a cube carb .
manufacturers & technicians who actually know what is going on rarely mention it as it is really not important

Thanks for the information. I reassembled the blower, primed it (pumps up the pressure in the tank?) and it started after just a few pulls. I took it out and found I still have a problem. It idles and runs up to about 3/5 power just fine but if I open the throttle completely it falters and the rpm drops off quite a bit. I don't have a ready method for testing the cap pressure/vaccum. Perhaps I just buy a new one? Or? I looked at the carb manual -- it looks like there are several places where junk could accumulate and give high speed problems but so could an improperly pressurized tank? Thanks for your time.

Did you put a kit through the carb ?
If so then which kit ?
The WYA series is a rotary valve type carb and if the engine runs up to 3/5 throttle then either the carb filter &/or main jet are clogged causing it to die lean
Or the metering needle is set to high causing it to flood out at higher revs ( causes higher input pressure )
Try it with the tank cap backed off 1/2 a turn & get back .

The "primer" bulb is really a purge bulb that sucks the air out of the metering chamber so it can be replaced with fuel.
So when the air rushes through the venturii it can draw fuel into the engine

I did not put a repair kit or take anything apart on the carb. I just took it apart enough to see the id. When I went to test run today it went right up to speed. 30 mins and some lower speed and lots of full throttle and idling. Only one little hesitation at full, then 15 min more at full.
Bottomline? YouARE royalty! He types, the foul-engine gods depart!
Thanks so much for your help but I have a hard time "fixing" something that's working. Perhaps I'll get back to you then.

Any chance to get some help with a homelite string trimmer?

A month ago It quit. The fuel line rotted out.. and i put some random kind of small hose into the fuel tank. It ran for a while but quit at about 1/2 a tank. Then it wouldn't start and I wound up buying and installing a new tank with proper lines and a filter. Now, on the first or second pull with choke on, it just fires a few times and quits. Massive cranking with and without choking, with and without throttle at full, yields nothing but a sore arm. A few hours later, same scenario, choke, pull, sputter.

It is the EM PS 01525 engine. Thanks in advance.

Please start a new thread for the trimmer or things just get confusing