FG110 mini tiller stalls when air filter cover installed

[Cfs]

I am quite confused. I am working on a FG110 mini tiller. It was not running it is now running but as I begin to install the air filter cover it will slow down and stall. This happens with or without the sponge air cleaner element being in place. Just putting the cover on stalls the engine. It is a Honda GX25 engine, there is a sticker with a bold type FY1* and the Serial # GCALT-2818115
The tiller is a model # FG110K1AT serial FAAA1528491.
I can get the tiller to start and run but as soon as I begin to install the foam element I can hear it slightly affect the speed the engine…slow it down. But it will continue to run. As soon as I begin to close the cover down over the carb with it without the element in it.. the engine stalls and quits. I do notice that the oil breather tube does seem to seep some oil into the air filter box and into the carb. I have disassembled and cleaned the carb and both diaphragms look fine, I did not replace either. I thought that there might be a slug of debris in the screen and there was not.
I have drained the oil and refilled it with 2.5 oz of 10W30. (Calls for 2.7 oz. and I wanted to avoid over filling) I did adjust the valve lash at one point which is how I got it to start and run.
Can anyone confirm the correct gap for both the intake and exhaust valves? . Does anyone have any other ideas on what I can try
Any and all input is welcome

Spit

 

[dougand3]

Small barrel carbs. I had one that the rotating barrel was worn and let too much fuel thru. Do you have a Throttle screw on carb? (I don't recall one). I had to get new carb.

 

[Cfs]

Small barrel carbs. I had one that the rotating barrel was worn and let too much fuel thru. Do you have a Throttle screw on carb? (I don't recall one). I had to get new carb.

There is a throttle screw. But I don’t think it could be the cause of this issue. It runs at high speed and idle until the air filter cover begins to close over the carb and then it cuts out. I have never seen anything quite like this. There is a hose I assume an oil breather hose, that runs from the top of the engine (at the valve cover) to the air filter box. It does seem to seep oil around the choke plate from this hose this oil migrates to the throat of the carb and that might play a part in it stalling. I had the carb off and cleaned most everything I know to clean but still have the issue. I can get a new aftermarket carb for less than $15? But I don’t think that will fix it. I am hoping someone else has had a similar issue and can shed sone light in this
Thanks Chucj

 

[PTmowerMech]

There is a throttle screw. But I don’t think it could be the cause of this issue. It runs at high speed and idle until the air filter cover begins to close over the carb and then it cuts out. I have never seen anything quite like this. There is a hose I assume an oil breather hose, that runs from the top of the engine (at the valve cover) to the air filter box. It does seem to seep oil around the choke plate from this hose this oil migrates to the throat of the carb and that might play a part in it stalling. I had the carb off and cleaned most everything I know to clean but still have the issue. I can get a new aftermarket carb for less than $15? But I don’t think that will fix it. I am hoping someone else has had a similar issue and can shed sone light in this
Thanks Chucj

Does is smoke when it starts shutting down? The AF is going to reduce the air intake. So the vacuum is going to be stronger. The piston is going to suck air harder from any where it can get it.
But it's strange that it would cause too much, unless there's something wrong with the AF.

Is the air filter somehow making contact with the butterfly? Or maybe the back one (closest to the engine) is binding on the back gasket?

 

[Cfs]

Does is smoke when it starts shutting down? The AF is going to reduce the air intake. So the vacuum is going to be stronger. The piston is going to suck air harder from any where it can get it.
But it's strange that it would cause too much, unless there's something wrong with the AF.

Is the air filter somehow making contact with the butterfly? Or maybe the back one (closest to the engine) is binding on the back gasket?

No it makes no contact to the carb whatsoever. If I move my hand in front of the carb while it is running it will begin to stall, so it may well have to do with the vacuum and drawing air in somewhere other than through the carb throat. I am going to check the gaskets on the carb where it mounts to the manifold

 

[Tiger Small Engine]

No it makes no contact to the carb whatsoever. If I move my hand in front of the carb while it is running it will begin to stall, so it may well have to do with the vacuum and drawing air in somewhere other than through the carb throat. I am going to check the gaskets on the carb where it mounts to the manifold

Unless the air filter is new, replace it. If it slows down and then dies when air filter is installed and tightened, then it is most likely restricting the air flow to engine.

 

[PTmowerMech]

No it makes no contact to the carb whatsoever. If I move my hand in front of the carb while it is running it will begin to stall, so it may well have to do with the vacuum and drawing air in somewhere other than through the carb throat. I am going to check the gaskets on the carb where it mounts to the manifold

If you had air coming from another source, then it wouldn't stall when you put your hand close to it.

Again, when it starts to stall, is there any smoke? If so, what color? Black or white (blue)

 

[upupandaway]

I do notice that the oil breather tube does seem to seep some oil into the air filter box and into the carb.

I've had that happen. Disconect the breather from the air filter holder so it doesn't pull air\oil from that hose and put the filter on(don't forget to cover the hole of the hose u removed). If it runs fine will confirm there is either blowby or too much oil i the motor as it is drawing oil into the carb thus bogging down.

 

[PTmowerMech]

Does this unit have some sort of PCV valve? It's a 4 stroke, so I assume it does.

 

[upupandaway]

Does this unit have some sort of PCV valve? It's a 4 stroke, so I assume it does.

Oh yeah, thanks. Forgot - so 3 causes...