787 Starting problems

[ian430]

I'm new here and just bought a Seadoo speedster 1999, twin 787, been sitting for about 18 months, one engine fires up fine but the other just fires on full choke at idle on one cylinder and the other cylinder seems to push fuel out/flood and not fire, if you add any throttle it stalls, carbies are new there are 2 good scratches on the rotary valve, was wondering if this sound like the rotary valve timing is out

 

[rusty nail]

did you clean the fuel tank, new fuel filters before running the boat with the new carbs. you could have easily sucked in dirt into the carbs. needed and seat suck open a little

 

[rusty nail]

or if the fuel lines themselves are beginning to go bad they should be replaced

 

[rusty nail]

i am assuming you checked compression on the cylinders.

 

[wayneh]

Don’t forget the spark plug. I’ve had one fail completely and suddenly despite looking fine.

 

[ian430]

Thanks for the thoughts, turned out the brass cog inside on the end of the rotary valve shaft has sheared which let the valve plate slip which put the timing out, pulled the shaft fitted a new cog re-timed it and fired straight up