Carb. tuning on Echo HC-150


LawnSite Member
Apopka Fl
Would anyone know what the factory setting is for the one hi-mixture adj. screw is in number of turns out is? As when I got this HC150 it was running vary rich, black plug, oil dripping out of the muffler etc. I turned the Hi speed adj screw in a few turns and runs accelerates much better and can idle forever if I let it.... but with non-eth 93octane fuel and Amsoil Saber mixed to 80:1 it really screams at wide open throttle but still smokes? so I would like to know if possible the factory setting of the Hi speed screw located by the primmer bulb. As i would like to tune this right and correct.

Thank you in advance for your help and input


LawnSite Platinum Member
Just a thought. Have you cleaned the exhaust port (and muffler) out and put in a new plug? The oil from being rich takes awhile to burn off before it quits smoking.

I don't know the standard turn out. I always go by how it sounds/runs. After that check the plug after running it and see what it looks like.


LawnSite Senior Member
Factory settings are not always correct--one of the most accepted ways to tune the hi-speed is: 1. run the engine to get to operating temp. 2. With engine running at full throttle, close (clockwise) the hi-speed screw until engine speed starts to slow down, keep count of how much you turn the screw and open it (counter-clockwise) until engine starts slowing down, then set the screw half-way in-between the two points.

For years I tuned by setting to highest rpm position. I think this is now too lean--especially with today's gasoline. Open a little past this point.


LawnSite Fanatic
chesapeake, va
GlynnC's advice is pretty much on the money. You don't want to lean it out too much ( max screaming rpm) or ya risk a meltdown! And with clippers ya got all that stuff movin around in there.

The " factory setting " that you are referring to is actually just the starting point to get it running. In your case it does'nt matter since it already runs.
It usually is 1-1/2 to 2 turns out from lightly seated.

Big Wes

LawnSite Senior Member
From the closed/seated position, open the H & L jets 1 full turn. Should start from there.