Honda mini tiller cuts off when start tilling. runs great when held above ground with no load. cut off seems to be associated with the movement and shacking when tilling ground.

You probably have a belt drive that has is not tight enough to pull under a load. The belt is pulled by an idler pulley that engages when you start the tines. Check the belts by working you engage lever and look for the belt and idler. More than likely there is an adjustment that will allow you to put more tension on the belt thus making it till. Do not do this when the machine is running! The belt should not have flex in it when engaged. It may a little effort to engage the tines when you get it tight enough to till.
Col. Dana Gillespie

Id say if its that new I would return it .Otherwise was it ever stored upside down or was it laying on its side
Its unlikely its a air filter issue with that low of use but you may want to check there to see if the oil is being siphoned up thru the breather line in the air cleaner area. lf the engine had been ran dry initially then there could have been damage done to the cylinder walls and the oil could be passing what is left to the piston rings,if this is the cause the unit would need to be overhauled .

check the shear pins on the tine shafts

Did you put in new gas, and the proper gas oil mix for a 2 cycle, if required? Be sure your gas lines are not cracked or hard, this can cause leaks and hose breakdown, ie carburetor issues.
If so you should try putting in some Sea Foam gas additive. Most auto parts stores have it, it is great and has solved a lot problems for me with out tear down.. Let it run a while, at med or fast idle, then come back later or next day and try to run it, after a couple of running sessions mine straightened right out.Carburetor may be gummed with varnish, the sea foam seems to help reduce that and with running time, eliminates it.

If the tines become jamed, the tiller will stop. This is especially true if you are preparing your lawn for seedng without doing an preparation of the ground. Also, check you accerleration line, there may be a loose connecton.. Otherwise, sounds like a service issue.

Check the piston rings and the valves. One of them is leaking.If you run the machine as is it will soon break down altogether...Lee

I took the transmission apart and the gears were fine. The friction pads on the centrifugal clutch don't seem to make full contact with the drum. Does anyone know what the thickness of the friction pads are suppose to be? I used some belt dressing on the pads and got some movement on the tines. With no wear on the gears, I guess I'll be replacing the clutch.

This seems to be a common issue as of late, i'd tighten up your idle adjustment so you can run at full throttle with no issue. The tiller's oil should be at the lower lip of the dip stick's access threading while the unit is laying face down (gas tank down). Clean up your carb as well and change your plug/filter, if this doesn't work than you're probably looking at some simple carb adjustments, but the fact it dies after 10 minutes of use makes me think it's running either dirty or too rich.

Hello, I think if you look at the depth setting bar you will find it clogged up with grass and roots. Once it clumps up you can't get it to drop to depth to make the cut. There are two speeds for the rear times for the toller which will make it go forward more slowly and allow the dirt clods to break up better. Also cut the grass as short as you can, make a shallow pass with the tiller 1" to 2 " to cut the heads off the roots and then go to depth with your next cut. This should pretty much break up the cloding when doing the tilling. Also watch it because it is hits a rock it will jump up and drag you away at the speed of the tines, because it lifts the drive wheels off the ground and the times drive the tiller instead. Other than that mine used to chew up everything including wet DG. Good Luck, RAC

I have had the same problem.
The first time the solution was to replace the rubber membrane underneath the primer bulb. Take off the bulb, then remove the plastic part underneath the bulb. There is a rubber membrane underneath that. The ethanol in the gasoline tends to deteriorate the membrane. The honda dealers sell them for about 14 dollars.

The second time the problem was caused by the gas cap, not properly venting. In this case the engine would start and run, but when I gave it full throttle, it would quit.
It got so bad that it wouldn't even run. I noticed when I loosened the gas cap it ran great.
So I took off the cap, removed the inner parts, and got a diaper in and pushed it though the holes in the plastic part underneath the cap, and through the rubber plug in the center. I did this a few times and check with my mouth to see if I could pull some air through the cap. When it breathed satisfactorily, I put the cap back on the gas tank and it ran great. Now it runs better than new.