formula z 583 is blowing fuel back into the air box... is there a way it could be out of time, if so iam guessing..i have to take the whole engine apart or is there an eaiser way? thanks in advanced. please any sugestions would help...thanks..

I havent had to do this yet but, there are no chains or cam internal to the engine...the mag plate is under the the recoil start and they have a shear key to keep them in place, that could be partitally sheared. As far as I know this is the only place you can time the engine. I think your probably looking more at weak/worn reeds, I have heard this can cause a similar issue but, havent had to replace them either...Good luck, I wish I had a better answer.

The 583 is a rotary cased mill( timed plate for the intake and exhaust strokes). This is located under under the carbs on the back side of the case.
There's ways to change that plate in *degrees but I myself never had to dig into one.
I remember there where different ones to change to for different performance gains .

The guy you really would need to talk to is.... in high performance tuning section in my signature, he runs the show there.

Sure it's not getting over fueled?, float seats, choke plungers hang open?? Round slide carbs ar known for float&seat problems . Reason saying , the float tab going to the needle gets bent and needs to be adjusted. It happens alot from cleaners bumping them around when cleaning and what not..even seen it from the factory.

fix/check...Take and flip your cabs upside down and make sure the tab touching the needle seat is closing the valve... and the floats are level, Bend the tab a bit to adjust accordingly.
If your dumping to much fuel in it will backfire and what not like it's out of time ... rotary valve closed and fuel is being dumped in.
...result .. back flash in the air box,it has to go somewhere.

I really think it's a fuel issue rather than timing .

mutt