MacKissic shredder not starting after jam

[pcs2011]

I have a MacKissic 12PT10 shredder. Rebuilt it (new hammers/spacers) earlier this year and has been running terrific since. The other day my wife was chipping some small limbs and it came to a grinding halt.

I removed the chipper chute and found some wood pieces jammed at the knife. I cleared them and tried to start?O GO!!

Today I removed the chipper side w. bearing and cleared some other small pieces of wood from the bottom of the chipper housing. Still would not start?. I rotated the rotor by hand (spark plug wire pulled of course. It rotated smoothly (maybe one area a slight drag).

My next move was to remove the belt and try to start the unit. Started up fine !!.

Now I am completely stumped. Would appreciate any suggestions as to what I might try next.

Thanks in advance,
Pete

 

[DennisArrow]

If it started with the actual chipper/shredder mechanism disengaged then it indicates that probably there is a "safety switch" someplace on that part of the machine that is not allowing the engine to start. More or less a dead man safety switch like the one on modern lawn tractor seats that kills the motor when you get off............

Go to the ignition of the engine and follow the wires back to their components. Bet you will find one that someway got shorted out...........God bless......Dennis

 

[pcs2011]

Thanks Dennis but I don't think there is an interlock. When I pulled the cord it acted like it wanted to start, then the cord was ripped from my hand...some kind of backlash thing.

Any other thoughts?

pete

 

[T_e_r_r_y]

Might have sheared or partially sheared the fly wheel key. Have to take off the shroud and nut-washer, then the fly wheel. Just looking at the key way. To see if it is still lined up, won't help to see if it is partially sheared. Timing is off if the pull rope is pulled out of your hand.
Others might chime in with some items to check also.

T.J>

 

[pcs2011]

Thanks T.J., I'll check it tomorrow.

Pete

 

[pcs2011]

Might have sheared or partially sheared the fly wheel key. Have to take off the shroud and nut-washer, then the fly wheel. Just looking at the key way. To see if it is still lined up, won't help to see if it is partially sheared. Timing is off if the pull rope is pulled out of your hand.
Others might chime in with some items to check also.

T.J>

Terry - One other question. You said possibly timing could be off. How would I check that?
Pete

 

[T_e_r_r_y]

The fly wheel and crankshaft have notches in them. The key(actually a soft piece
of aluminum) is used to line up the fly wheel and crank shaft.
This piece of soft metal is made just for these occurances. Object suddenly stops and motor is still wanting to turn and run.It shears or partially shears, instead of breaking another expensive piece on the motor.
The key lines up the magnets,so they pass the coil at the same time every time.
These magnets on the outside of the fly wheel,as they pass the coil, a electric current is created and sent to the plug, to fire the gas mixture.
You will need to get the numbers off of the motor.
Some are on a plate- riveted to the shroud,some are stamped into the shroud and some are on a decal.
If you have electric start- the numbers might be under the push button for the electric start..
Need all the numbers,model-type and code.
Any and all numbers from the motor will be help full to the parts man at your local small engine dealership.
Also be sure to bring the key to the parts man.
There might be different keys to fit the same motor.
Hope this helps you in getting it in the shredding mood!!

T.J.

 

[pcs2011]

Terry - Thanks for the fantastic explanation :thumbsup:!! And I bet you are correct that this is the problem. I should be able to to get to it by the weekend. Stay Tuned; I might have a few questions as I take things apart...

Thanks again..
Pete

 

[T_e_r_r_y]

I'm not a mechanic or anything like that. (38 years of railroading- 58 yrs old)
Just roaming around different forums, mostly small engine forums.
Like to read just about all the problems different people have with mowers-snow blowers-small riders and garden tractors.
I don't mean to step on any ones good ideas or possible solutions.
When you said the pull rope pulled out of your hand, I had to give my thoughts on the possible solution.
If the key is the problem and you get the shredder going. GREAT!
This might help the next chipper/shredder owner that has had the same thing
happen to him.
If this doesn't get it running. others will check the posts to see if is running or not.
They will offer other things to try/check .

T.J.

 

[pcs2011]

Hi Terry - Found the numbers (Engine Model, Type, and code). Also found some nice .pdf illustrated parts lists on Briggs and Stratton Engine Parts.

I'm attaching two photos which show the shredder engine.

My sound like a stupid question, but which side should I attack from; the pull rope side or the reduced side?