how did this happen?

[Karts of Kaos]

im fixing a golf kart for someone and we think it has a sheered flywheel key because its backfiring out of the carb and not starting. but how would that happen because there's a cvt and things like that so how would you shear the key if there's no hard stops on the engine itself if you know what i mean.

 

[Denny]

What kind of golf kart? And what year is it? Pictures would help also. In 12 years of selling and servicing them never heard of one shearing a key in the flywheel.

 

[Karts of Kaos]

Well I took it apart today and it had not actually sheared a fly wheel key. What other things could cause an early ignition? It's a Yamaha engine with a cdi type ignition.

 

[jmaack]

Timing chain or belt? possibly out of time.

 

[Karts of Kaos]

nope its an ohv not ohc i already checked the valves and so did the guy before me

 

[Denny]

Carb full of junk, fuel pump bronze air filter dirty, bad pick up ign module, bad coil.
unfortunately no way to test pick up/ module if you try it will fry.

 

[Karts of Kaos]

what about the igniter/ cdi box thing. is it possible to test that

 

[Denny]

Absolutely not! If you try it you will fry it!! Is there any spark at the plug? If no replace, if yes look some where else.

 

[Karts of Kaos]

so why does the cdi fry if you test it?

 

[Denny]

I never understood that exactly but I found out the hard way trying to test a brand new one to keep track of the values. Put it in the kart still no start (the parts were new from sealed bags). Ordered new module and igniter and bam fired right up. I should have listened. For me an expensive lesson for a useless piece of paper with writing on it.

 

[Denny]

As for the question in your thread title.
when mommies love daddys they have a wrestling match. The mommies always loose so they have to go to bed with a real silver dollar under the pillow. It makes them real uncomfortable for the 9 months or so they have to carry the silver dollar around. The they have to use the silver dollar to tip the stork when he delivers the new baby. And that’s how babies are born.
Now keep it secret, don’t tell anyone.

 

[Karts of Kaos]

wow
also update: i did end up getting it running when i hooked up a battery jump box but it still backfires out of the carb on acceleration. it also accelerates very slowly. idk if thats normal for golf carts bc i dont work on them much. i have messed with the carb but it didn't seem to make a difference.

 

[Karts of Kaos]

heres where im at

 

[Snaker]

Does the flywheel or case have timing marks?

 

[Denny]

There are no timing marks because the timing is non adjustable. I would do a compression test or leak down test wet and dry and compare numbers. You will probably find you may have to pull the head because the valves or guides are worn out. If they are you can bet the cylinder, piston and rings are too. Compression test numbers should be around 120. Higher or lower are a sign something is not right. A flat cam is another possibility.

 

[Karttekk]

im fixing a golf kart for someone

Did you ask when it first started doing this? Did they change anything? Did they buy it like this? Sounds like it's missing. Bad coil or coil wire? Burnt or sticking valve? Valve spring?

 

[Karts of Kaos]

um i believe the owner never had it running so im the first one to get it running. he thinks the timing is off but i cant really fix that. thanks very much denny ill check the compression and see what it says and ill talk to my customer after that.

 

[Denny]

The engines are only designed to run reliably for so many hours. It is called planned obsolescence. Very prevalent in the golf kart world. Manufacturers wanted courses to buy or lease a new fleet every 4 years. They made more money on leases. The factory’s figured out they could make more money by selling more karts to the dealers and golf courses.

 

[Snaker]

um i believe the owner never had it running so im the first one to get it running. he thinks the timing is off but i cant really fix that. thanks very much denny ill check the compression and see what it says and ill talk to my customer after that.

If you can get the timing specs, you can find TDC and make your own timing marks.
You might double check for factory timing marks first.

 

[Karts of Kaos]

thats smart, ill try it, thanks