lawn mower only runs with choke open?

musicislif

first of all, before i diagnosed this as being the issue, i completelty dissasembled the whole engine, and reassembled it. Ive cleaned the vlaves thoroughly and i grinded the exhaust valve just a hare as i was pretty sure there was an issue with compression and via the info ive found online i thought that would cure it. but it still does the same thing it did before i did any work, which is only starting for 2-3 seconds IF i prime the hell out of it. but i recently found that if i keep the choke wide open it will run, and run good. but as soon as the choke is closed to normal position, it dies.

and yes, ive replaced the needle, spring, and seat in the carb and have made sure that the jet in the hex bolt is clean. this pariticular carb works just fine on my other identical mower (4.5hp tecuseh), so i have to doubt that the issue lies within the carb.

the only thing else i can think of is a possible air leak somewhere, but all of the gaskets looked just fine and intact when I put everything back together. COULD this issue be a symptom of an air leak???

Any Ideas or thoughts will be much appreciated. Thank You!!!!!!!!!!
in response to mustangers answer....im a little confused. if the choke is left "open" while using the mower, allowing maximum amount of air in, this seems like it would cause a lot of unnecessary wear on the engine, not to mention a waste of gas. wouldnt this be like revving the engine non-stop?? it makes more sense to me to let more air in in order to start it and get it going, then back it off to a normal idleing speed. im only cutting the grass here, not racing it........That is how i position the choke when using the other identical mower, and it works fine that way.

And if im wrong (which i may very well be) the engine should still run, if not start, with the choke in the closed positon which it is not doing. Thanks again everyone!

Answer
Well, you've got the choke open and choke closed idea backwards. Choke open is the normal running position. Choke closed closes of the air supply and puts more gas into the engine.

Now to answer the question, I'll bet if you go get a $4 carburetor diaphragm gasket, the engine will run just fine. Have you checked the key in the flywheel? Sometimes they will be partially sheared and it throws the ignition timing off. But I am thinking it is definitely an air leak issue. Maybe the tank has a crack in it where the carb screws on? I have seen that before and the cracks can be hard to see. One way to find it if you want to go through the trouble, get some india ink (art supply stor will have it) and put on the suspected area of the crack, wipe it off and put some baby powder over the entire area. The baby powder will draw the ink out of the crack and it will show up plain as the nose on your face. The only other thing I can think of is maybe the head gasket is not sealing.

If and when you do find out what is going on, please update. Interesting question.

How do you rate Honda Shine bike (in India) in these fields.......?

bamboo

Ratings should be out of 10
Looks
Average/Mileage
Pick up(in 125 cc segment)
Reliability
Comfortness during long drive
Honda Servicing in Service Stations
Price (in 125 cc segment)

Answer
I am sure it the ugliest POS in the whole country, and thats saying quite a bit. I have lawn mowers with bigger engines.

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