engine problem, need some help

[vandancouver]

just got my first go kart (at the ripe age of 26)
it was a old clunker until i completly took it apart, rebuilt the engine (5hp briggs from 1984), and re did everything

over 4th of july weekend we were all having a good ol time with it when all of a sudden it kinda did a bang and a few sparks came out...then it died. now when i pull on the rope it just spins and spins..there is still spark. i think* i broke the rod/piston but im not to sure. i pulled out the spark plug and looked in there as a i pulled, and didnt see any movement. thats where i would look isnt it?

when i say it spins freely..the whole shaft type thing does, but not the gears..nothing catches at all, hard to explain. ive never blown a rod so im not sure.

any ideas?

the model # of engine is 130232-1638-04-84111309

you can see it on the briggs website..

if i just need to buy a new engine i will. just curious if its a possible/economical way to fix this

thanks alot,

dan

p.s. sorry i didnt see this seciton of the forum or i wouldve posted here first

 

[pmat]

Check your flywheel key, it would be the cause of what you described, and it could easily have sheared if you didnt torque it back on to spec when u redid the motor.

 

[vandancouver]

it isnt the flywheel key i know that for sure. if it was just the flywheel key it would still spin the whole motor just the timing would be off, etc

 

[pmat]

I believe its a sheared key, but it could be the crankshaft. very unlikely but possible. yesterday i broke a rod in my mower, and everything would spin but the piston wouldent move.

 

[vandancouver]

the piston isnt moving. i pulled the plug out and looked inside for movement as i pulled..and nothing was happening. it was still getting spark though. i didnt hit anything or stop hard, etc to make the key shear. but i guess ill check that too.

my wifes brother thinks (he says he knows) its the rod

 

[pmat]

If it is the rod; the clutch or whhatever you have at the end of the shaft, should still move. its not easy to break a crankshaft.

 

[vandancouver]

it does still move at the end, but it dosent move the actual gear that spins the wheel etc.

hard to explain but when i pull i see the crankshaft spinning, the thing that the pullstart spins is still spinning, and its spinning on the other end of the crnakshaft...but not grabbing a gear. i guess ill check the flywheel key..but when i pull the plug nothing is moving uderneath

 

[pmat]

now that u say it that way, it does sound like a rod, its worth checking the key before u replace the rod or whole engine.

 

[EagleTalons]

Umm...You did remember to put oil in the engine right?

 

[vandancouver]

just changed it that day;. so yes