Motor shaft does not rotate freely to start engine

[JimNic]

Hello Everyone... I am hoping someone will be able to assist me with my mower problem.

I have a Toro GTS 6.5 Recycler (bought used); it has a Tecumseh motor in it. The last time i used this mower (6 weeks ago), it started and operated with no problems; it is stored in a dry, protected shed.
Today, (10/24/11) i went to start the unit, and after pulling the cord, I got about 12 inches of cord and engine shaft stopped rotating. Everything that you're supposed to do to start the Toro was properly done. I have since disassembled the outer housings and covers and gotten down to the shaft of the motor itself. When i rotate the unit by hand, it will turn 7/8 of the way without a problem, then it stops... but with signification effort (strength), i can rotate through the bind. Afterward, the shaft will then rotate for another 7/8 rotation and then come the bind area again. The bind area seems to be an arc of about 1/8 of a turn (45 degree swing). I have removed everything visible that would be a hindrance to turning the shaft (motor), but it still binds at the one point in a 360 degree sweep. The brake, auto cutoff, etc... everything has been disengaged, but to no avail!?

Thanks Everyone... any suggestions or assistance would be greatly appreciated.

N.B. - Oh... there's humor in all of this... I live in Northern Colorado, It is Oct. 24th 2011, it was 78 & sunny today; but now we have a small snowstorm coming in tomorrow night (we're expecting 6" to 8") and my grass REALLY needs to be cut, go figure :^)

 

[ILENGINE]

take the spark plug wire off and ground it. remove the spark plug and then crank the engine to see if it still binds. If it does a posibility could be that a piece of carbon has come loose from the head and not letting the piston rotate past top dead center. you may be able to keep rotating the shaft and break up the piece of carbon or you may have to remove the head.

 

[possum]

Have you looked under the deck yet?

 

[JimNic]

take the spark plug wire off and ground it. remove the spark plug and then crank the engine to see if it still binds. If it does a posibility could be that a piece of carbon has come loose from the head and not letting the piston rotate past top dead center. you may be able to keep rotating the shaft and break up the piece of carbon or you may have to remove the head.

Thank you... I will try your suggestion!

 

[JimNic]

Have you looked under the deck yet?

Yes... and it's not an issue, I removed the blade, even though it was not binding or preventing rotation. I also made sure that there were no other possibilities of external interference.

 

[Bill Crowell]

I have the exact same mower and engine, and the same thing happened to me just the other day. I disassembled the engine and found that something had caused the piston to score the cylinder and transfer metal to it, resulting in a loss of compression. I'm replacing the engine with a Kawasaki FJ180V.

 

[JimNic]

Bill Crowell,

Thanks for commenting... this is a big help and I will do the same if that's the problem. Unfortunately, I'll have to wait until spring. I live in Northern Colorado and we just had our second snowstorm... I can't get to my shed :^)

Thanks everyone... I appreciate your help via your comments... I'll stop back in the forum as soon as I get a chance to pull the motor apart and find the problem! JimNic

 

[motorrefurb]

If I understand right, you turn it clockwise 7/8 of the way, and then turn it counterclockwise 7/8 of the way? If that's the case then maybe your exhaust valve is stuck shut :frown:

 

[benski]

I think when you come out from under the winter's snow, you'll find you have a broken rod.:frown: Just my guess, but if it fetches up with kind of mechanical feel to it, that's my guess.

 

[JimNic]

If I understand right, you turn it clockwise 7/8 of the way, and then turn it counterclockwise 7/8 of the way? If that's the case then maybe your exhaust valve is stuck shut :frown:

Hi motorrefurb, almost correct... i can turn the shaft 7/8 clockwise and, as i try to turn the final 1/8 to complete one rotation, that 1/8 of a turn takes a tremendous amount of strength to complete it. So, 7/8 of a rotation is easy to hand turn, 1/8 requires two hands and a lot of strength. It happens in the same spot every time and i can get past it, but only with great difficulty.

Thanks for your comments and suggestions!