# Walbro WT. Help ??



## B8mn1 (Oct 12, 2008)

Hello everyone!! I am new to the board and did some reading and searching, but only found a little info, thought maybe someone could help in my exact situation..

I have a McCulloch blower.. Initially I think I had fuel line disintegrate so I replaced both the fuel and return lines,, the filter flows good...

I ran it for a while then could not get it to prime... I took the WT apart and cleaned it.. No luck.. Bought a rebuild kit, $12.00  , took it apart and cleaned it all and put it back with new parts , gaskets, and metering pin.. No luck...

When I pump the prime I get air.. it forces air / fuel back into the tank but no pickup of fuel to the carb.... I read and finally tightened both the Hi / Low adjustment screws and the primer bulb pumps the fuel in 3-4 pumps,, I can even feel the vacuum on my tongue (when there is no fuel and I put a line on the main fuel port).... When re-connected to fuel tank the carb fills with fuel...

from reading other posts,, It seems I have an air leak in the metering gasket (on the pump side) but I replace it with the new one and even tried the old one... always the same problem..it is not drawing fuel, just sucking air

When I open the hi / low adjustments,, I can hear the vacuum from pumping the primer bulb.,, It sounds like air is being drawn in from the venturi...

Someone,, please throw a suggestion my way,,, I gat a day and a half in messing with this thing ,, and really need to get it running..(my yard is looking pretty bad)!!!!!!

Thanks,
Ben


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## geogrubb (Jul 28, 2006)

I'm a little confused as to why you shut off the high and low, screw them both to seat, then back them off 1 1/2 turns each, this should get it running, then at WOT set the high until it runs the best then back it off until it just starts to sound like a 4-cycle(if you leave it running too lean you will burn it up). Now adjust the low so it runs as smooth as possible then adjust the Idle rpm the way you like using the throttle idle adjustment screw. If you used the new metering arm from the kit, I would suggest using the old one unless it was very worn, as it has the correct height setting. Have a good one . Geo


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## B8mn1 (Oct 12, 2008)

geogrubb,

I had both the hi and Lo adjustments closed because that was the only way I could get the prime bulb to draw fuel into the carb.... 
If either was open the bulb would just fill with air...

I put it back together and still got lots of air in the primer bulb... but I was able to fire it up,,, I adjusted the high and low adjustments and it was running good.......

I probably need to turn the Hi adj back down just a bit, 'cause at WOT it is sceamin'...

not I have to get the weedeater going....

Thanks,

Ben


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## 30yearTech (Sep 14, 2006)

You have a leaking check valve in your carburetor, this is why it will not prime unless both needles are closed. Most likely it's the high speed check valve in your carburetor. These usually don't come in a rebuild kit. Sometimes once you get the carburetor to prime with these jets closed, you can reset them and the engine will start and run alright after adjusted.


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## B8mn1 (Oct 12, 2008)

30yrTech,

How do I replace the check valve??

Thanks,
Ben


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## 30yearTech (Sep 14, 2006)

What are the numbers off your carburetor. In some cases the check valves are not replaceable and the entire carburetor must be replaced. Sometimes the check valves can be replaced, it depends on the specific model of your carburetor.


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