If you are in decent shape, you could spend a few hours doing it with a fork. Manti are not really designed to break sod. . Also unless the hubby's chainsaw was a 4 stroke, the mix isnt the problem . IIRC, Mantis wants 50:1 That is what most chain saws use too.
I'm not impressed with your mechanics.. They took the easy way out and changed easy stuff, Charged you for the parts and minimum charge for 10 minutes work.
Get the engine running and let it warm up. When it stalls, try to start it Give it some gas if it tries to start but doesnt check the spark I think I remember reading about a run of faulty coils for Echo engines. Research that on google

OR
The lack of use probably got to the carburettor and clogged something. All I can say is that other than a throttle cable, I have not had any trouble with the the Mantis I inherited from my folks . It runs fine on the rich 32:1 fuel I mix for everything. You can take the carb apart and spray cleaner through the little passages. Then re-assemble. Set the main jet 1 1/2 turns out . and the low speed to to 2 turns . If you googled ' fixing a Mantis carburettor' you may get lucky and find a you tube video . Its not rocket surgery .

I would just like to comment that, in my opinion, putting a two-cycle engine on a tiller is kind of silly. You need extra weight to help force the tines into the soil. I think the Mantis tiller is available with a good 4-cycle Honda engine. It might weigh a little more (and cost a little more), but I think it would work better all around.

ZM

The weight was never an issue. When it was working right it was fantastic. (Just don't expect it to chop up long grass. bad idea.) but once the long weeds are out of the way, this thing had no problem digging into the dirt.

but now it just runs sickly. And quits. Constantly.

I just don't have the patience to try and become a mechanic. Twice now I've had mechanics try. IF the guys who know what they are doing can't fix it, I'm sure I can't.

It's just not right and I'm sick of fighting with it. Got it outside right now as part of a yard sale for ten bucks.
Not sure if I even want to replace it. For what little use I get out of it. May as well stick to the back breaking task of doing this with my spade. sigh.

If you were within a 100 miles , I'd buy the 10$ Mantis in a heartbeat

Im in SW michigan. Where are you?

If you were in the Grand Rapids area, I'd give you $20.

I drive from Hartford to Holland all the time. Kid lives up three. Grand Rapids isn't far from it.
I'd be happy with 20.00. The thing gives me a pain. I just worked on my yard today with a good old shovel. slow going but it works.

Hey, Holland is having it's first outdoor PRIDE fest June 29th. Sat. They are hosting craft booths this year and Ill be one of them. If your serious, Ill haul the thing up to my kids house to hang onto. Then I could put it in my car the day of the show.

My user name here is also my domain name. You can find my email on that site.