Tiller idles but won't run at high speeds

My tiller starts fine and will idle for as long as let it without stalling, but when I pull the throttle to make it run at high speed (tilling speed) it stalls out. No matter how long I let it warm up it still stalls when I try to use it.

The gas is new, the oil is new and the air filter is clean.

Anyone have any idea what’s causing this and how to fix it?


When you advance the throttle quickly does it sputter and slowly die out or does it quit suddenly? Usually IF it sputters it could be the low end adjustment on the carb is too rich. If it dies quickly the low end could be too lean.

Sounds silly but could the choke still be engaged?

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Bart… Just some backyard thoughts…

You could have a small piece of debris in the carb that once you open up the throttle demanding more fuel clogs the jet. or the choke could be partially closed and when opening throttle stalls due to lack of air.

Does it smoke when you try to crank it up or does it sputter and die? My guess is debris in the carb… this has been my experience.

Some engines have a primer bulb and you can prime it while throttling up you slowly forcing fuel in. If the engine goes to full throttle as you prime it… this could be a sign that fuel is not getting in. Don’t over prime… just push it to keep motor running. I you use the below link and prime it… sometimes it will force the debris through…

You can purchase this:


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Bob - would that product be similar to seafoam?


Good question… Seafoam is a great product as well. I know it can be used for small engines as well … I can’t say that it works as well or if not better than Start Your Engine. I have had good results Start Your Engine in similar cases like Barts. I use Seafoam more as a preventative on some of my other equipment and toys.


Try taking the top of the air cleaner off and covering the top of the carb with your hand when you accelerate the throttle.

Sometimes a vacume hose cracks and lets air in…

Sometimes a fuel line cracks or becomes loose and lets air in…

Sometimes a gasket dries out a little and lets air in…

Carb mount screws could have loosened…

Plarkplug may have the electrode burned off…

I think BobC might have hit on something with his debris observation. When my older Subaru did that the mechanics told me to take off the air filter and choke off the air intake. Use a heavy glove or thick chunk of rubber or some such. Run the engine, choke it off, and try again. It puts a lot of suction to the jets and can clear a small clog pretty well. Worked well for me.

I also like Seafoam, but caution against using it in an older engine that has never had it, at least in the crankcase. Some people feel that the strong detergents remove too much from high mileage engines and can allow leaks and such to develop.


Thanks folks!

I was messing with it a little and have two new data points. When I quickly pull the throttle, the engine quickly cuts off. No stuttering at all.

The other one is a little strange but may shed some light on the problem. I somehow got it to run for a bit on full throttle but after 15 seconds or so, it would start to die so I had to let up on the throttle to keep it going. I did tbis a few times…it would run on full throttle for a bit but then start to die until I let up on the throttle.

I finally just held down the throttle and it ran on high for 20 seconds or so and then it died. [break]. I wanted to be sure I was describing it properly for this post so I started it up, let it warm up a little, rev’d the throttle a bit and then fully opened it up and it ran and ran and ran and never cut out!!!

I haven’t tried it in dirt yet, but does this mean that there was some sort of blockage that was cleared?


You might have clear the debris. Some time some good high octane gas letting it run for awhile can clean it out as well. You can get varnish like build up on the bottom of your float bowl that can gum up your engine. Crank it up and let it run… let us know how it goes.


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In my experience a blockage rarely clears itself…Try putting it in dirt and see what happens…I agree with @BobC high octane gas and some sea foam would be the first place I’d start…not sure how often you use your tiller, but most people put their equipment away without properly draining at the end of the season…varnish in the bowl will create all kinds of problems similar to what your describing. the sea foam will help dissolve it.

Running Too lean

If that’s the case the lesson to be learned is to either run your engine dry every fall or use a stabilizer- some people insist on running it out but I’ve had good luck with Sta-Bil. And it’s easy …


I would use stabilizer and not run the engine out of gas.

It may have been mentioned already, but never put gas with ethanol in your small engines. Find a place that sells non ethanol premium and only use that type of gas. I also put Stabil in the premium right away. That way you know the gas is treated from the very start. Since I started using non ethanol premium treated with Stabil right away I’ve had zero problems with any of my small engines.

Finding non-ethenol gas in my neck of the woods is next to impossible.

Sometimes you can get Avgas from a small airport/somebody who flies.

Yes I can get a gas here but it’s 100 octane Low Lead. I know people that run it in dirt bikes and chain saws but there is mixed reviews about using it small 4 stroke engines. Plus it’s twice the cost. Not too big a deal for chain saws where your only going through a couple gallon all summer long but it adds up in a riding mower that burns 4 gallons/ week.

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Here’s a site with a list of places to get non ethanol gas http://pure-gas.org/

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Thanks all !

I was able to do a little tilling with it yesterday. It ran, but it was a little rough. I had to keep letting up on the throttle when I heard it starting to die.

I did run it to dry last fall but I don’t think I put any stabilizer in my gas. I’ll start doing that regularly and I’ll try some of that “Start Your Engines” stuff. Thanks for the gas finder site too. Very cool!

Folks -
I need a little more guidance.

I tried the “Start Your Engine” and ran it for a while on idle, but I still had the same problem where it would cut out when I opened up the throttle. I then added some Sea Foam and had basically the same result…it would idle indefinitely, but wouldn’t run for long at full throttle.

I must admit that I’m not sure if I used either product correctly. The directions were a little vague…“pour half the bottle in…” I added both materials to the tank with existing gas in it and ran (idled) it for 10 - 15 mins. Neither the Start Your Engine or Sea Foam made a noticeable difference, but I’m not sure I used either correctly.

I’m wondering what to do now?

  1. Should I run it dry or drain the tank and then try Sea Foam or Start your engine without any real gas?
  2. Should drain the tank, add some (how much?) new, high octane gas and add some (how much?) Start Your Engine or Sea Foam?
  3. Do the same as option #2 except use ethanol free-gas?
  4. Do something else entirely?

Thanks for all your help!