Motor cranks but won't turn over

scottdg

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Let me start by saying I am not an engine guy but I try to get as much done as I can before seeking professional help.

My YT3000 stopped in the middle of mowing recently. I replaced the battery and it started but after running for around 30 seconds it started blowing smoke. The engine had to be replaced a year or so ago because gas had leaked into the engine and the guy that repaired it put a valve in which I close after using. It was open for a while though while I replaced the battery. After doing some research I checked the oil and thought it smelled like gas although I could not be certain. I took the carburetor off and cleaned it out and checked the float and pin, replaced the air and oil filter. Now it won't start. I checked the plug to make sure it is getting a spark and it is.

I don't know if there really is gas leaking into the oil or not. Any suggestions on first why the mower will not start? Secondly on what might have been causing the smoke in case it continues after I get it started.

Thanks,
Scott
 

bertsmobile1

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Sounds very much like a head gasket.
If fuel leaked into the cylinder while you were replacing the battery and you cranked the engine with liquid in the cylinder it will blow the head gasket.
Depending upon how bad the gasket blows you can get a little smoke or become a James Bond mower in no time flat. :laughing:
Not a difficult job to replace the gasket but if the carb leaked that much fuel it really needs looking at.
 
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Well 2 reasons can make an engine smoke, A very clogged air filter or over filled oil.

You stated you had an oil filter.

Is your tank under the seat frame ?? If so you have a fuel pump on your engine. If you have a Briggs or a Kohler engine then you might have a bad seat in the carb that is leaking back in the crankcase causing you to MAKE oil. Gas getting in there.

Post the make and Model of your Engine .............
 

willys55

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welcome to the forum Scott......

does the engine turn over freely, and crank over at the correct speed. and listen to bert, it could be a head gasket for why it wont start now, but what made it stop running in the first place....my money is on the engine being bogged down externally or internally like a bearing or worse
 

Pumper54

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You said you cleaned and checked the carb and changed the air and oil filter, did you change the oil also? If so how much was there? If you did change the oil did the stuff you drained out look and smell like it might have had gas in it? Over filling the oil and/or a stuck float valve can lead to the issues you had, if by some chance you hydrostatically locked up the engine you can clear it by removing the spark plug(s) and cranking over the engine but watch out for all the mess that will come out of the spark plug holes. Head gasket(s) are fairly easy to replace.
Tom
 

willys55

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that's a good point as well, if too much oil in the crankcase the pressure in the crankcase from the piston trying to motorboat through the oil will also cause it not to start
 

scottdg

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Well 2 reasons can make an engine smoke, A very clogged air filter or over filled oil.

You stated you had an oil filter.

Is your tank under the seat frame ?? If so you have a fuel pump on your engine. If you have a Briggs or a Kohler engine then you might have a bad seat in the carb that is leaking back in the crankcase causing you to MAKE oil. Gas getting in there.

Post the make and Model of your Engine .............

Briggs EBSXS.5402VL

The air filter wasn't that old and the oil had not been filled since the beginning of the season. The tank is not under the frame. The mower had been running fine and then just stopped in the middle of cutting. Like I said it wasn't until it had been sitting a week or more that I started having the smoking issue after the valve was left open.
 

scottdg

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You said you cleaned and checked the carb and changed the air and oil filter, did you change the oil also? If so how much was there? If you did change the oil did the stuff you drained out look and smell like it might have had gas in it? Over filling the oil and/or a stuck float valve can lead to the issues you had, if by some chance you hydrostatically locked up the engine you can clear it by removing the spark plug(s) and cranking over the engine but watch out for all the mess that will come out of the spark plug holes. Head gasket(s) are fairly easy to replace.
Tom

So when I changed the oil the beginning of the season I put too much oil in so I drained it until it no longer smoked. It has been running fine for four months. I thought the oil I drained smelled like gas but I am a bad judge. I thought it may be a stuck valve which is why I took it apart. I thought that was the easiest thing to try first. I did remove the spark plug last night to check to see if I was getting a spark. The engine crank as if it wanted to turn over but won't.

I am willing to give the head gasket a try. But that shouldn't keep the mower from starting correct. I want to get it started to see if it was the float. If not then I can consider other options for fixing the smoking if it continues.

Oh and I made sure I didn't put much oil in when I refilled it. It is actually toward the low end if anything.
 
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Wow I missed a bunch of posts on here.

Ok you have the 21 HP Briggs on that one I think. It doesn't matter what HP you got. What does matter is you have a OHV valve engine. Unless someone swapped the engine on it.

In response to your question about the engine starting. You stated that you took the plug out and it would not even turn over as in rotating ??

Well if the battery is good and you have a good solenoid and a good starter, then you do have a internal issue.

Try to jump the engine with your truck/car. But put the red cable on the starter stud. If it turns over you are good on that issue.

Ok too much to type for now.

Let us know when you try the above said. Plus Tard Mon Ami !~!~!
 
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