I have a Sensation mower with a 4 HP Briggs engine. It has sit idle for many years after I had used it and broke off the blade from the spindle when I hit a piece of carpet outside. The blade was/is fine but the bolts on the spindle broke off. It is very difficult to pull the starter cord to get it started now. It does pull but not far and I can't get enough speed built up in the pulls to get it turned over. The things I have tried are as follows:

I have taken off the starter cover and the engine does spin easily with a wrench turning the bolt on top.

I have taken out the spark plug and the starter pulls easily without the plug in.

I have tried spraying starting fluid in the spark plug hole and in the carb but it does not start.

I have heated up the plug with a torch to clear away deposits on the plug.

I have checked the engine brake mechanism and it is not binding the engine.


The engine does have oil and I have put new gas in the gas tank.


If anyone has any suggestions, I would greatly appreciate them, THANK YOU.

 

I have also now removed the top bolt fixture on top of the flywheel so that I could see if the key was sheared off and the flywheel was displaced (because I understand that might affect the timing and cause kickback) and the key looks perfectly fine and is centered in the slot.

To clarify the pull on the cord, I can pull the chord out the whole way, but it is hard to pull and I cannot do it fast enough to generate enough speed to get the mower to fire (I assume).

 

Take the plug out and blade off and have someone slowly pull the cord while you watch the crankshaft. It sounds like it's bent, and it will wobble and not run true while it is turning if it's bent.

 

I tilted the mower on its side and pulled the starter chord and as I watch the spindle turn on the shaft, it does not wobble or spin at all funny. It appears true. As I said, I can pull the starter chord out the whole way, but not easily enough and quick enough to get it started (if it did fire, which I do not know as of yet, but do expect it would). I am strong enough to pull it hard, believe me.

 

Well, that's good that the crank isn't bent. Check the engine brake. The cable on the handlebar bail that you hold before starting goes straight to the kill switch and engine brake. If this cable isn't working, it won't release the brake.