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JD Loechelt
JD Loechelt, Small Engine Technician
Category: Small Engine
Satisfied Customers: 23
Experience:  10 years as technician at Rental Company- internal AND customer repairs
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Lawn mower starts but cuts off! Why?

Customer Question

My lawn mower initially starts but then cuts off and won't start unless I let it sit for a while but them it wont stay running
Submitted: 9 years ago.
Category: Small Engine
Expert:  JD Loechelt replied 9 years ago.

There are a few possibilities here, most likely of which is flooding. To determine if this is the case, you can remove the spark plug and see if it has unburned fuel on it. Flooding is usually caused by a restricted air filter which doesn't allow enough oxygen for the fuel to burn. Another possibility is water in the fuel. Try to take a look at the tank with a flashlight, water will separate and sink to the bottom. If the fuel is old or has water in it, drain and replace (also would want to drain fuel from the float bowl on the carburetor. Next possible cause is low oil, make sur it is up to level indicator. If none of these solve the problem, we can check some other things too.

Customer: replied 9 years ago.

I changed the gas and replaced the spark plug. The oil is fine as the mower is only 4 month old. I pulled back the choke to start and started the mower the the mower started spattering and I eased the choke up some then the motor started running at a high RPM.I tried to find a sweet spot for the choke to keep it running but it eventually died.This happens every time I start it. This is a Yard Machine product.

Expert:  JD Loechelt replied 9 years ago.
the mower dies once the choke is all the way off, and then it won't start again? Does the exhaust look black?
Customer: replied 9 years ago.

It runs at a really high RPM when the choke if off and then it dies. The exhaust is clean.If I wait a few minutes, it will start again and the cycle begins.

Expert:  JD Loechelt replied 9 years ago.

The high rpm's is a problem. There should be a governor spring that controls a linkage attached to the carburetor. take a close look, see if you can find any problems there. Has the spring been moved? Do all linkages/ moving parts seem to move freely?

Customer: replied 9 years ago.
JD...All the sprinngs and things are there but it definately cuts off when I try to turn the choke off. When I slowly turn the choke off it starts running real high and then cuts off like maybe it flooded?It runs rough with the choke on so I can't use that way.
Expert:  JD Loechelt replied 9 years ago.
Make sure all bolts on the carburetor feel tight and the butterfly valve on top moves freely, if there are any air leaks, it won't run with the choke off. Is the air filter clean and dry? If it is flooding, the exhaust smoke will appear black.
Customer: replied 9 years ago.
Yeah,everything is clean and tight. It just wont work with choke off. Maybe replace the caburator?. The exhaust is clean except when it gets ready to cut off then it turn a little black.But, by then its a second fron cutting off.
Expert:  JD Loechelt replied 9 years ago.
Strange, black smoke indicates too much fuel, I would expect that at full choke, not the other way around... Have you tried draining the float bowl on the carburetor? When you drained the gas, was there water in it?
Customer: replied 9 years ago.
I drained everything.It seemed to run a little better after that but it has since gotten worse.Matter of fact immediately after, it ran quite well and then I turned it off and ran it again and then it started doing it again
Expert:  JD Loechelt replied 9 years ago.
Ok, let's clean that float bowl out better. Pinch the fuel line off so tank doesn't drain, remove the float blow completely and clean w/ carb cleaner and/or compressed air. If the bolt that holds the bowl on has a tiny port on it, make sure that is clear too. I think this will solve your problem once and for all...
Customer: replied 9 years ago.
I tried that again and no luck. I give up. I am never buying a Yard Machine product ever again. I spent $250.00 4 months ago. They give a 3 month warranty and it scraps out in four months.By the time I get this one fixed I could have bought a new one or a decent used one. Thanks for your help
Expert:  JD Loechelt replied 9 years ago.
I'm sorry, your frustration is understandable. People wonder how industrial grade mowers can be worth the $600 or more that they cost, but when it comes down to it, the average mower just isn't built to the same standards.
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