# Adjusting fuel mixture on Mantis tiller



## MariaAZ (Jun 5, 2007)

My mother has a two year old tiller. It started fine and ran great for a few hours. Since I'd been working in rather dusty soil, I took a long break and decided to change the air filter. The one installed was a thick white filter, the one I replaced it with was a thin reddish one that came in a kit from Mantis. The filter undoubtedly was the original, as it hadn't been run very much in the past.

After changing the air filter, the engine wouldn't stay running. I could get it started but not keep it running unless I was able to get to the throttle trigger fast enough. Once I gave it just a little gas, it ran fine as long as I kept a light finger on the trigger. 

Looking at the trouble-shooting guide in the manual, and experience with adjusting car carbs, it sounded like the air/fuel mix was off. I followed the instructions in the manual concerning turning the red screw completely counterclockwise and the white screw to the halfway point, and now the darned thing won't start at all.

Any hints/tips would be greatly appreciated. The Mantis manual, I've discovered, isn't exactly a wealth of in-depth information!


----------



## TNHermit (Jul 14, 2005)

Turn both screws al the way in then 1 turn out. See if it starts. If not go to 1-1-/2

Two strokes have to be tuned while running and an 1/8 turn can make a huge difference. start with the low jet first. It will be a PITA to turn it while its running but its the nly way I know. Do the high speed last and make it so it runs a little rich. the kind of oil and the mix can make a huge difference. I use a good grade MX oil and run about 32-1
From your description of your filters I say it was running rich. Do your filters need to be oiled. Are they foam or paper?


----------



## MariaAZ (Jun 5, 2007)

They're paper, and the manual doesn't mention oiling so I'm assuming one puts them in as-is (though assuming ANYTHING can be dangerous I know!)

I'll play around with the low jet and see if I can get the blasted thing to turn over. It seems to "pop" just fine when I'm trying to do a cold-start and pull the choke all the way out, just nothing when I put the choke back in. It's funny... I find dialing in the dual SU carbs on my cars a lot easier than this tiny little gizmo!


----------



## TNHermit (Jul 14, 2005)

MariaAZ said:


> They're paper, and the manual doesn't mention oiling so I'm assuming one puts them in as-is (though assuming ANYTHING can be dangerous I know!)
> 
> I'll play around with the low jet and see if I can get the blasted thing to turn over. It seems to "pop" just fine when I'm trying to do a cold-start and pull the choke all the way out, just nothing when I put the choke back in. It's funny... I find dialing in the dual SU carbs on my cars a lot easier than this tiny little gizmo!


Does yours have a primer on it. Those little things unusually have a button you push two or three times to prime. Try starting it while holding the throttle wide open. if that don't work then put the choke full on and try it that way. these little things have a combination lock sometime when it comes to starting


----------



## MariaAZ (Jun 5, 2007)

It does indeed, I make sure there's gas in the little bubble. I never thought of holding the throttle open while trying to start though. Definitely have to give it a try. This is a new-to-me machine, and luckily I just discovered how easy the attachments are to take off the axle! Thanks for the help


----------



## foxtrapper (Dec 23, 2003)

The main mixture screw you tune by running at full throttle. Adjust it up and down until the engine barely 4-strokes under full throttle, no load.

The idle mixture screw you adjust by letting the engine fall from full throttle and make sure it simply doesn't stall. Not as easy as it sounds btw.

Idle speed screw you typically adjust so that the engine is just barely twitching the tines at idle.

Personally, I tend to pop the plastic limiter caps off the screws.


----------

