LA 105 Mower Stalls at WOT

[Greyhair73]

19.5 HP B&S engine. Emptied tank, cleaned and blew it out, blew out fuel line, replaced fuel filter, drained carb bowl, new air filter, new oil filter, new spark plug-all from JD maintenance kit. Starts only at nearly closed throttle, will idle and run ok up to about 1/2 throttle, then stalls out at WOT. Help? Thanks!

 

[Kish318420]

Carb,
Check float and inlet valve, sticking and opening up to let enough fuel in to keep up with demand. Also check fuel solenoid it may be sticking too and not opening enough also.

 

[beenthere]

Is there directional flow to the fuel filter, that it is in wrong..?? just a WAG

But given that it probably was doing this before replacing the filter, likely not the problem.

 

[Ron of Va]

Definitely a carburetor problem. Buy a carburetor rebuild kit and rebuild. There are a lot of Instructional videos on YouTube to show you how, if you are not familiar with them.

If you are not comfortable rebuilding the carb, then just buy a new carburetor and swap it out. I think you will find a new carb is relatively cheap these days. The last time I checked on carburetors the new carb was not much more than the rebuild kit.

As a matter of fact, I just put a new carb on my sons Honda push mower, and it was less than $15.00 for a brand new one.

 

[tomplum]

I wouldn't go so far to say that it is definitely a carb issue. Could be a worn cam lobe for that matter. Or the choke stuck shut. Or? BTW a new carb will run in the neighborhood of 125$ on these. Lots of good advice above about checking fuel flow etc., though you didn't give us any history. Had it start to lose power slowly? What did you find when you had flushed out the fuel system?

 

[Spanner]

The carbs are expensive on these engines. But plenty of them died due to the head gasket failure 'weakness' so there will be second-hand carbs at your local JD dealer for sure. Maybe beer-vouchers will work!
Sounds like the main jet is blocked and it is only running on the idle circuit in your carb.
Some more history would help, agreed..

 

[leonz]

19.5 HP B&S engine. Emptied tank, cleaned and blew it out, blew out fuel line, replaced fuel filter, drained carb bowl, new air filter, new oil filter, new spark plug-all from JD maintenance kit. Starts only at nearly closed throttle, will idle and run ok up to about 1/2 throttle, then stalls out at WOT. Help? Thanks!

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Before you spend anymore money replace "ALL" the fuel lines from the tank to the fuel pump mounted on the side of the cooling air cowling and from the fuel pump to the carburatuer as it sounds as if you have a collapsing fuel line causing all your aches and pains.

 

[Richard001]

Greyhair73,

Welcome to TBN. Good to have you here. Hope you find the issue on you machine OK..

Richard

 

[Dave M7040]

Likely emulsion tube "A" under main jet has some of its tiny holes plugged.

To remove the main jet "B" you must have a screwdriver tip that exactly fits the slot in the main jet because if you damage the slot with a poorly fitting screwdriver you are in a mess. You need to push down hard while turning to keep the bit in the slot.

The emulsion tube tiny holes often need to be poked out with a fine strand of wire.

Dave M7040