Dies at low idle

Howdy Y'all! I picked up a little Murray push mower on Craigslist for $10 that the owner couldn't get to start/run. Pretty sweet deal for me... I cleaned it up, changed oil, replaced torn primer bulb, changed spark plug (old one was fouled, even after cleaning it, gave weak little yellow spark) and gapped it to .030, replaced air filter, and most importantly removed and cleaned the carb. Added fresh gas (stabilized with Sea Foam), primed it 3 times and it started first pull (which thrilled me, considering I'm only in it now for about $23 and about 2 hours of my time). It runs, but when I move the throttle to lower speeds, the idle isn't smooth (even after I let it warm up)... it sounds like it's surging. And if I get too close to the little turtle, it dies (there's no stop sign next to the turtle that's supposed to kill the engine... the control cable is supposed to do that). I remember my dad's old mower had a couple of screws on the carb to adjust idle speeds, but this carb doesn't seem to have any... looks like capped off holes where screws could be. Any suggestions on how to properly tune this?
The model engine is B&S 128802-3130-E1. Thanks!

The new carbs are all fixed jet carbs per EPA. No more homeowner adjusting. If it has an idle speed screw, I would adjust that so the engine will idle. It should idle at about 1200 rpm. The Seafaom should help the idle, too.

Thanks Indy... maybe I'll put a tiny bit of extra Sea Foam and let it burn through a whole tank before worrying about it. I need to cut the grass this weekend anyhow. Maybe it will take care of itself that way. If not, I won't worry about it... it runs on high speed and it cuts grass, so not a bad deal for the $23 I've spent on it.
Also, thanks to RobertBrown for correcting me. The mower doesn't actually "idle," the throttle is speed control.
Quick responses on the thread posts... y'all rock! Thanks.

It's possible that your machine may need some carberator work. I bought a used snow blower that was doing something similar. It's not very expensive.

I did clean the carb replaced the bowl & bowl gasket, had to do that just to get it to run. I ran gas with extra Sea Foam in it this weekend for about an hour, still dies if I take speed down to low. On high it works great, so I'm not going to worry about it. In fact, why would they make adjustable speed anyhow? Most mowers don't have adjustable speed.

eeguns said:

still dies if I take speed down to low. On high it works great, so I'm not going to worry about it

Click to expand...

For a walk behind mower... If it runs well at the business end of the RPM scale... that is all you really need.
BE happy, mow... :smile:KennyV