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So my Lawnboy wouldn't start. I figured out the problem and it seems that my air intake valve is stuck in the wide open position. If I close it by hand, it will start and stay running no problem. Then I open it up just alittle bit and runs very good and strong. But when I let go, it wants to go into the wide open position again and the mower turns off. So what I did was put a bolt in to hold it in the half open position. Runs great now. But what I want to know is it this is ok to do? Or should I try to clean it? What is the best way to try to clean this "stuck" valve without having to take the whole darn motor apart. Could I spray carb cleaner into the air intake valve itself? Will this loosen up the valve?

Any suggestions would be appreciated?

Hello deltabox, & Welcome to this Forum...
I've been around carbs on all sorts of engines for many decades ...
I have never heard of an 'air valve' on a gasoline engine ... until ... twice today

Some Diesel engines have 'air shut off ' valves, for insuring an engine shut down, to prevent a run away, during very abnormal situations...

The 'valve' you are referring to, in a gasoline engine is a CHOKE plate... and anytime that the engine is running at normal temperature it should be WIDE open...
If you are having to choke it to keep running you have a fuel delivery problem.
Continued use of the choke will cause a very rich mixture that will wash the lube from the cylinder wall and destroy the rings. You need to find the problem and insure the choke is wide open when the engine is running...
Good to have another Lawnboy enthusiast here... :smile:KennyV

So can you give me any suggestions on how to clean this out? Is it probably a gummed up carburator or something like that? What would cause the engine to turn off with a wide open valve? Should I spray cleaner right into the carb through the gas line or maybe through the air valve?

It is a restriction somewhere in the fuel delivery system... anywhere from the tank and on into the carb... a carb/injector cleaner (mixed with the fuel, at the correct ratio, see can) may clean out the gunk that might be causing this...
With the choke partially closed the engine vacuum through the carb is assisting in pulling in the fuel... That is not the normal way to pull fuel into the engine and will lead to troubles...
of the fuel addative will not do it ... then you will have to take the carb apart, (not that hard to do) and clean it up then reassemble ...
since you have it running (with partial choke) you may as well give the easiest method a try... if it doesn't clear up, post back and you will get a step through on carb cleaning...:smile:KennyV

Thanks Kenny. I will get a carb cleaner additive today and try it out. Once I add it into the fuel, how long do I need to run it before i know it is not working? So can I spray cleaner directly into that air valve thing also? Will that help any?

Also, I noticed that the valve stays wide open even when the engine is off. Is that normal "off" position? I'm guessing no.

deltabox888 said:

Thanks Kenny. I will get a carb cleaner additive today and try it out. Once I add it into the fuel, how long do I need to run it before i know it is not working? So can I spray cleaner directly into that air valve thing also? Will that help any?

Also, I noticed that the valve stays wide open even when the engine is off. Is that normal "off" position? I'm guessing no.

Click to expand...

It should start cleaning almost immediately ... depends what is gumming it up, could take 1/2 the tank of fuel...?
Spray through the air passage won't hurt anything, but most likely will not clean the fuel passages...
Once it is cleaned up the normal flow of fuel will generally keep it clean... :smile::smile:KennyV

I looked up a video of how to clean your mower carburator. Doesn't look too complicated. I think I'm gonna fiddle with it and see how it turns out.

Tell me if this sounds right? Remove air filter. Remove air filter holder. Remove main jet under bowl. Clean main jet. Remove bowl and clean it. Remove float and clean it. Put everything back. Should I go deeper into the little bits of the carb or does this sound good enough to take care of my problem?

There are a few other threads that cover this same type problem... fuel delivery....
Give a look at this one: http://www.lawnmowerforum.com/craftsman-forum/3215-fuel-delivery-problem.html
wildbill has s rather simple approach if it is just a cleaning of the bowl thats needed...
Give it a quick read... :smile::smile:KennyV

So I cleaned the carb today. I removed the air filter. I removed the air filter housing and bracket to access the carb. I removed the main jet under the bowl. I removed the bowl. I cleaned out the main jet with cleaner and poked the holes with a tiny needle. Cleaned the bowl real good. Got rid of all traces of dirt/debris that I could see. I removed the spark plug and sprayed through the air intake valve. As it came pouring out of the spark plug outlet, it was brown and dirty.

Let it sit for awhile to dry up. Put everything back including a new air filter and spark plug. Took a few pulls to prime the gas back into the carb, but I'm proud to say -- THE DARN THING RUNS LIKE NEW AGAIN !! Starts on first pull now and is running strong. :biggrin:

pb blaster spray everything take out the plug and let it set overnight