The tiller starts and runs well for about 10 to 15 minutes but then will bog down and stop running . It will restart and run for about 30 seconds and then stop again. Any ideas about what is causing this, the tiller is only 18 month old and should not be giving this kind of trouble

Could be fuel tank not venting properly. Run until the symptoms repeat then loosen fuel cap. If it starts and runs ok then likely the vent (cap?) Is plugged.

Otherwise it's likely a crankcase leak.

belt may need to be replaced

Check your coils and spark plug leads and the plugs themselves. All these things are prone to breaking down under heat when they are starting to fail.

you might want to check for spark when it stops running

I also was having issues with an old 5 horse Troy Built tiller that would fire when gas was in the tank then stop running. If it's a Briggs and Stratton engine like the one I have it's probably you can remove the muffler to gain access to the side of the carb. Remove the four screws and the cover off the fuel pump diphram and check to make sure that the rubber isn't cracked or degraded. I replaced the one I had and it now runs like a champ.

Hello. you have some gunk in the carburator. Get a can of starter fluid or carburator cleaner aerosol and a helper. Remove the air filter and start it up. Spray a little starter fluid into the air cleaner to keep it running for three or four minutes and the problem should clear. If it does not clear the carburator will have to be disassembled, cleaned and rebuilt. j.

Probably just clean the carburetor. it sounds like its not picking up enough fuel to sustain itself

Ok I have r Royobi Tiller (30CC Gas) And last year it ran fine after rebuilding the Carb. This year it was "hard starts" Idles fine, (Tiny whisps of blue smoke in exhaust with correct ratio) Even seems to run better with the choke "on" but still...at idle only. as soon as I touch the throttle...its bogs down in tune with how much gas I give it. Little throttle? Little bog down, Little more throttle? Almost stalls, a normal throttle rev? it stalls dead! Then starts right back up again in 1 pull and idles fine again!? WTF? So after cleaning a clean carb again, (twice) and seeing no change I thought I'd go look at the original diaphragm and compare it with the rebuild kit diaphragm (which is the one in the carb.) And guess what? The replacement has a larger rivet by a factor of "2". So basically it was flooding the carb, I bent the needle tang down, better but no cigar. But I could rev it half way now. A second disassemble to bend it yet a bit further and Vrooom vroom vrooom ****! So check your needle valve even though you think its 100%. (Especially if you rebuilt the carb with a kit!)

Sounds like you may have a bad motor. If the motor is overheating it will shut down on its overload.

If its a shorted contact in the timer you could mark the spot where it stops and restart it again. It should stop exactly at that point.

Check to see if the gas cap is clogged. If the gas cap is clogged, it will keep the carburetor from getting the proper gas flow. Try this: The next time it begins to die, loosen the gas cap. It should begin to run again. If it begins to run again, then you know it's the gas cap.

Jim