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Craftsman 12 hp Rider Mower won't start.


cbursk's Avatar
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08-06-04, 06:30 PM   #1  
cbursk
Craftsman 12 hp Rider Mower won't start.

Any insights would be appreciated.
I have an older 12 HP rider mower that has been running great. Halfway through a mow, with the motor giving no indications of a problem, it let out a loud pow! sound followed by tons of white smoke from the front of the engine.
I immediately turned the key to OFF and the motor shut down after running for a few more seconds. When the engine had cooled off and I got my courage back, I tried to restart the engine to see what would happen. It does not start up and just cranks over and over without firing.
Is the motor toast? Any ideas?
Thanks!

 
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08-07-04, 07:59 PM   #2  
i dont think its ignition. i have had coils go out with no pow or smoke. they just wont start until cool down or coil replacement. i dont think its the engine because it turns over. i think it is dirt plugging up carb. i had a 72 dodge with a bad fuel pump that would leave white smoke everywhere. take bottom bolt off carb bowl. let float drop and wash out the garbage stuck in needle i am guessing. empty float bowl. put float bowl back on and bolt it up after you get gas flow from fuel line to needle and seat area.

 
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08-08-04, 12:35 AM   #3  
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When you tried to restart did the engine seem to crank faster than normal? Since it does turn over spin it by hand and listen or feel for any sounds internaly, also feel for a rebound as the piston comes up on compresion,(or with the spark plug out put your finger over the hole as you spin the engine and feel for pressure) if it has any left. How is the oil level? How does the oil look?
If it passes to this point as normal check for spark.

 
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08-08-04, 09:42 AM   #4  
cbursk
There is a round screen at the center of the top of the engine. I removed the screen and hand turned the wheel clockwise. There is plenty of resistance as you turn it. However the plot gets thicker. The air filter looker pretty dirty and even a little slimy so I thought I would take it off to see if the engine would fire without it. When I took the air filter I found that the reason it was slimy looking was because it was coated in oil and there was even a good amount of oil pooled under the filter. I cleaned this and then tried to start the engine without the filter in place. The engine stills turns over and over but never fires - same as before. There is a little opening in the center of where the air filter was that is pushing out air as the engine cranks. No oil was discharged while the engine was cranking.
Any ideas?
Thanks again!

 
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08-08-04, 10:27 AM   #5  
Azis
As you turn the wheel you should notice a difference in resistance, it should be easy for part of the rotation then feel resistance then easy again as the piston goes beyond compresion stroke. This is important as if compresion seems normal the valves can be ruled out for now.
If you remove the large nut on top of the flywheel, you may be able to view the shear key on the shaft. If you are unable to see it removal of the flywheel is next. If the key is sheared it will need replaced and should solve your problem.

 
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08-08-04, 02:57 PM   #6  
cbursk
When I turn the wheel it does behave as you say it should. Resistance increases and then lets off. So it doesn't seem like that is a problem.

 
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08-08-04, 03:52 PM   #7  
Azis
Thats a good thing
I still think the key could be a problem.

 
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08-08-04, 10:08 PM   #8  
steel flywheel keys very seldom sheer. i had a aluminum key sheer on a pushmower. valves needed ground and lapped on that one. on my tractors oil in air cleaner has happened when breather tube clogged, running engine at excessive speed, clogged air source to carb, piston ring wear, and faulty misfiring ignition (intermittent grounding out of plug wire.) pull plug wire out , put another plug in it ground outside of this plug to block with piece of wood. if spark is blue troubleshoot carb. spray staring fluid in carb or spark plug hole. if it acts like it wants to start and dies you know its carb. also try new plug. try these steps before you pull flywheel or cylinder head. it could be something simple.

 
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08-09-04, 03:19 PM   #9  
Smell your engine oil. Does it smell like gas? Is the oil now "overfilled"? The white smoke usually indicates gas in the oil. The bang is excessive gasoline being ignited by a hot muffler. The cause of this is within the carburetor and warrants such to be reconditioned. Let us know the previous questions' answers.

 
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08-09-04, 06:52 PM   #10  
cbursk
Additional info. I pulled the cover off of th engine and there is a square-ish piece on the front that has the letters OHC on it. This is where the smoke was coming from before. I pulled the spark plug and it was a little wet but not too bad. When cranking it does give off a spark. Also I tried cleaning things up with carberator cleaner to see if that help but it didn't. In fact after cranking it over a little the engine stopped turning over and instead there was a pretty nasty grinding sound coming from the side of the engine.
What do you guys think - am I wasting my time on this? Time to give up on it?

 
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08-09-04, 08:26 PM   #11  
Hello cbursk!

Don't worry, the starter gear is bad, causing the grinding. About $4.00-5.00 for a new one. That's not why it won't start though. We need the answers to the other questions to help you further. Especially about gassy smelling oil and oil level. Possibly a push-rod/rocker arm problem too.


"Who is John Galt?" - Ayn Rand (Atlas Shrugged)

God bless!

 
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08-10-04, 06:38 AM   #12  
cbursk
The oil doesn't smell like gas to me, but it does seem to be a little overfilled. I had added oil before this happened.

 
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