You probably have varnish in the fuel filter in the tank,the fuel hoses and the carb. Will take some disassembly to get them all cleaned out. You can try mixing some carb cleaner strongly w/ some gas/oil mix and try to circulate it thru the carb w/ the primer pump.
Mike

The Mantis also came with a kit that includes plugs, air cleaner and gasket for the carb. I should be in good shape to take it apart and clean it.

During the process I adjusted the screw for rich / lean. Any tips on re-setting it?

Thanks!

Don't know how old yours is but mine has two gas mixture screws. Low speed(black) and high speed (red),both with builtin stops.Are you adjusting the idle speed screw??
Mike

its probably the carb gaskets. rebuild the carb and you should be fine. the low and high speed screws should be one turn out. screw them all the way in and back them out one full turn. if you have the black and red stops on the screws, pop them off with a screwdriver. you dont really need them. hope this helps.

Is the carb re-build straight forward? I have not re-built a carb in about 20 years :) But I am up to it

I assume I need to hit a Mantis dealer for the parts??

get the name of the carburetor, it will be either a Walbro, Zama, or Tillotson. get the diaphragm kit, no need to get the entire rebuild kit. about $8.00. there will be some numbers stamped on the carb as well. you will need these. 2 gaskets, 2 diaphragms. when you take it apart you will see how easy it is. hope this helps. be sure to remove the needle within the carb as well. it has a very small spring under it, so be careful. better to take it apart on a white towel so you can see the parts.

niroja,

Thanks for the advice regarding the removal of the stops on Mantis products. Bought one of their edgers and after a couple of seasons I just could not get it running right. I played around trying to adjust it for more then an hour or two and still the problem persisted.

With your instructions it took me all of 5 minutes to get it running at top speed.

Thanks again, rredogg

The echo engines seem to burn more fuel. Why this happens is currently being debated. Whats up is in an echo engine which was used on the Mantis, when the fresh air/fuel mix hits the hot exhaust port it carbonizes. This carbon eventually plugs the exhaust port. Of course unburned fuel and cheap oil also help. Take a 5/16 socket or a phillips screwdriver and remove the muffler from the cylinder. You will be able to see the exhaust port. Using the pull starter, slowly cycle the piston up and down in the cylinder to get an idea of where everything is at. Slowly cycle the piston to the very bottom of its travel. Using a short stick or a dowl rod -no metal- scrape the carbon out of the port. Clean it all out and put it back together the way you took it apart. If you are concerned that you pushed some of the carbon dust back into the cylinder, then remove the spark plug and blow out the cylinder with some compressed air. Should take about an hour to do the job. When your done it should run like a clock.
Good luck,
Bob.
By the way, this is a 50 hour maintenance procedure on almost every two cycle engine.