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I hit a stump with my small push mower and afterwards it started vibrating horribly like your normal bent blade.

I took the blade off and it's bent somewhat. I figure this is the vibration.

When I had the mower turned on its side to remove the blade, there was oil running out of it from... somewhere. It saturated the air filter atop the carb but the carb itself has no oil in it. It is also running out of the muffler.

I topped the oil off and went to pull - it was very hard to pull, 'sticking' as I pulled it and would not start. I figured I'd bend the rod, crankshaft or something.

Upon dissassembly, I can see no visible damage to the internals and it rotates fairly smoothly, but - there was a puddle of oil on --top-- of the cylinder.

Could that oil have been causing the hard pull starting? I'm thinking of just putting it back together but I don't want to do that and discover there is something damaged that I'm just not seeing. I wonder if I just tilted it on its side during the time of the stroke where the oil was able to run through an open valve or something and leak out and into the muffler.

3.75hp 'Sprint' B&S pull start engine.

If you would have took the spark plug out and pulled it a few times you could have saved a bunch of time and work.

NEVER lay a mower on its side with the carb down

(( racing is the only sport that you need two balls ))

I guess you're saying that oil in the cylinder is my only problem.

You know I just realized that when I took the cam out it probably needs to go back in a certain way. I did not mark it. ???

--- ok got it. Line up the notch with the dot. I'm going to clean the gunk out of the cylinder and reassemble.

silver007 said:

I guess you're saying that oil in the cylinder is my only problem.

You know I just realized that when I took the cam out it probably needs to go back in a certain way. I did not mark it. ???

Click to expand...

Go on and google your engine model and look up how to time it.

And yes the oil on top of the piston was your only problem.

You tube will have a video on how to put the cam back in.

Sorry can not help you with that part

(( racing is the only sport that you need two balls ))

With the bent blade, it could also have partially sheared the flywheel key. That would make it hard to start too. When you turned the mower over, the oil went down into the carburetor, and down into the cylinder and into the exhaust when you pulled it over. Had you taken the spark plug out and pulled it over, I'd say it would have shot oil out like a whale surfacing! When you tore it down, you saw what remained of the oil that was in the cylinder. I doubt if it hurt the engine, but I have heard of connecting rods getting bent on account of "Hydraulic Lock" as they call it in the business. Especially critical on multi-cylinder engines where one or two may have oil in them and the other 4 fire off. That tremendous pressure will bend something. But in your case, I doubt if the rod is bent. A new blade and fresh oil and she'll probably run.

Thank you all. I have gaskets on the way so hopefully it'll run fine when reassembled. This engine has been great.