# Is my engine damaged?



## duke0001 (Apr 21, 2009)

I have a 3.5 Briggas lawn mower. When I used last Sunday, I fill it up with refresh gasline, But I forgot to fill engine oil. Then I started mower successfully. After one or two minutes, motor stopped. I re-started engine again. Mower run and stop again in less tan 2 minutes. At this moment, I realized that I didn't put engine oil in. So I went to buy engine oil and fill it up. After that, I couldn't start engine again. I just felt the rope to start up engine very loose. My question is: Is the engine of mower damaged due to run without engine oil in very short time? If it is damaged, how can I check to make sure?


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## Maytag (Dec 10, 2007)

When engine "quit" did it just act like it ran out of gas (ie. a few sputters and it slowly wound down to a stop) or did it act like it just hit a stump and "slam" to a stop?

First half of the above question would indicate more of a fuel/carburetor issue, second half of question would indicate more of the no oil issue. 
How much oil did you have to add? Did you add a few ounces or a whole quart or so?

If it stalled peacefully it almost sounds like your carb is dirty or gas cap isn't venting. If you now have the right oil type and amount in the engine try running it with the gas cap loose enough so air can get in without gas splashing all over.

I am not an engine repair guy so you might want to wait for some other responses before trying what I suggested.

My penny and a half - good luck -Maytag


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## duke0001 (Apr 21, 2009)

Maytag:

thanks for your info. The engine quit like it ran out of gas. After last use in 2008, I cleaned all gas tank and engine oil out to keep fuel injector clean. This time, I don't think it is fuel/carburetor problem. When I tried to start engine by pulling rope, the rope is loose and it seems that the spark plug didn't work. If I chage a spark plug, will it help?


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## chuck_thehammer (Oct 24, 2007)

I would try to start over,

drain out gas from tank and carb, get fresh gas (1 gallon) add 2.6 oz of 2 cycle oil to it, install new spark plug. without oil in the gas the spark plug could have overheated and failed.

best of luck, Chuck


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## duke0001 (Apr 21, 2009)

chuck_thehammer:

Thanks for advice. I will try these steps to see the result.


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## duke0001 (Apr 21, 2009)

Maytag, Chuck:

It was no luck. I cleaned carburetor and replaced the new spark plug. The mower still couldn't be started. When I pull cord, there was no spark and flywheel was loose. It seems that flywheel didn't engage into the magneto to trigger the ingition coil to function. So where should the problem be?

If I need to replace all parts and the cost may be more than buying a new one. Is this worth it?


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## Gocart (Mar 28, 2008)

No spark, loose flywheel. Sounds like you have a sheared key. Remove the flywheel and inspect.


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## duke0001 (Apr 21, 2009)

Gocart:

Where is the key that has been sheared? When I run the mower last time, there was no any sign that some parts were sheared or cut off. How could this happen? Please give me more details. How to know the key was sheared? If the key was broken, what step I should take to fix it? Thanks a lot for your help.


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## phillipmc (Jan 27, 2008)

The flywheel ke Gocart is talking about is a small keystock looking peice of alumnium that keeps the flywheel inplace on the crankshaft. It is designed to sheer if your engine stops suddenly to avoid engine damage. It will also sheer if the flywheel is loose. That being said.

Remove the cover the rope goes into from the engine.
Remove the bolt/starter clutch thats in the center of the flywheel and you might have a big washer there. Remove it also and look down the middle to see if the flywheel key is sheared if it is replace the flywheel key (most lawnmower replair shops have them for a $1 or so put it all back together makeing sure to tighten your flywheel back down tight as you can but dont go crazy with it (50 ft lbs or so of torqe should be enough)


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## duke0001 (Apr 21, 2009)

phillipmc:

Thanks a lot. I will try it with your instruction and come back to report the progress.


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