JD ZTR no start and back/afterfire

[Soundguy]

stepdad has a JD ZTr.. maybee 10-12ys old... Not sure of what model it is. 2 cyl He mowed with it 2 days ago. wouldn't start yesterday.

When i got there he had put new inner/outter air filters in it and changed spark plugs.

it turns over good.

I pulled both lines to the plugs and held them back and it has snappy spark.

while turning over it will occasionally fire thru the exhaust like a gunshot report.

It did it twice thru the intake, blowing the breather cap off the filter canister, the canister latch door off, blew both filters out, and caught the plastic canister on FIRE!.. same gunshot report.

i pulled the 4 10mm bolts holdign the valve covers on thinking it might have a bent pushrod, or otherwise valves hanging open.. but nada, valves and pushrods all seem to be moving well.

Checked the fuel pump, turning over it is producing great flow.

You can make the plugs get wet trying to start repeatedly or using choke, so it is for sure getting fuel.


At this point, i'm wondering if it has a keyed flywheel like a pushmower, and maybee it is sheared or partially sheared throwing timing off.

Ideas?

Thanks

 

[Zebrafive]

It definitely sounds like it has jumped time. What engine?

 

[Soundguy]

i think kawasaki.. but i was too distracted cleaning up from the 'fire' to remember.

 

[bjr]

One of the twin cylinder engines Kawi, or Kohler (I can't remember which) had a plastic camshaft gear for a while and I guess it would go out without warning. Just do a Google search on plastic camshaft gears and see what you get. bjr

 

[Soundguy]

will update what i find, thanks